A2Z Computer

ICSE Solved Paper, 2014

2022-05-21T09:48:00.006+05:30

ICSE Solved Paper, 2015

2022-05-20T19:22:00.001+05:30

ICSE Examination 2015 – 16 (Solution)

COMPUTER APPLICATION
Class – X
SECTION – A (40 MARKS)
Attempt all questions

Question 1:

(a) What are the default values of the primitive data types int and float? [2]

Ans: The default value of int is 0 and the default value of float is 0.0f.

(b) Name any two OOP’s principles. [2]

Ans: Abstraction, Encapsulation, Inheritance, Polymorphism.

(c) What are identifiers? [2]

Ans: Identifiers are names of variables, classes, packages, methods and packages in a java program.

(d) Identify the literals listed below:

(i) 0.5

(ii) 'A'

(iii) false

(iv) ''a'' [2]

Ans: - (i) Floating point literal

(ii) Character literal

(iii) Boolean literal

(iv) String literal

(e) Name the wrapper class of char type and boolean type. [2]

Ans: The wrapper class of char type is Character and the wrapper type of boolean type is Boolean.

Question 2:

(a) Evaluate the value of n if the value of p=5, q=19 [2]

int n = (q-p) > (p-q) ? (q-p) : (p-q);

Ans: n = 14

(b) Arrange the following primitive data types in an ascending order of their size: [2]

(i) char (ii) byte (iii) double (iv) int

Ans: byte = 1 byte

char = 2 bytes

int = 4 bytes

double = 8 bytes

(c) What is the value stored in variable res given below:

double res = Math.pow("345".indexOf('5'), 3); [2]

Ans: 8.0

(d) Name two types of constructor. [2]

Ans: Default constructor and parameterized constructor.

(e) What are the values of a and b after the following function is executed, if the values passed are 30 and 50: [2]

void paws(int a, int b)

{

a = a + b;

b = a - b;

a = a - b;

System.out.println(a + " , " + b);

}

Ans: 30, 50

Question 3:

(a) State the data type and the value of y after the following is executed : [2]

char x = '7';

y = Character.isLetter(x);

Ans: Data type of y will be boolean and value will be false.

(b) What is the function of catch block in exception handling? Where does it appear in a program? [2]

Ans: catch block catches the specified exception type and handles the same. It appears between try and finally block.

(c) State the output of the following program segment is executed: [2]

String a = "Smartphone", b = "Graphic Art";

String h = a.substring(2, 5);

String k = b.substring(8).toUpperCase();

System.out.println(h);

System.out.println(k.equalsIgnoreCase(h));

Ans: art

true

(d) The access specifier that gives most accessibility is and the least accessibility is _____. [2]

Ans: public, private

(e) (i) Name the mathematical function which is used to find sine of an angle given in radians. [2]

(ii) Name a string function which removes the blank spaces provided in the prefix and suffix of a string.

Ans: (i) Math.sin()

(ii) trim()

(f) (i)What will the code print? [2]

int arr[] = new int [5];

System.out.println(arr);

(i) 0 (ii) value stored in arr[0] (iii) 0000 (iv) garbage value

(ii) Name the keyword which is used to resolve the conflict between method parameter and instance variables/fields.

Ans: (i) (iv) garbage value

(ii) this keyword

(g) State the package that contains the class : [2]

(i) BufferedReader

(ii) Scanner

Ans: (i) java.io

(ii) java.util

(h) Write the output of the following code segment: [2]

char ch;

int x = 97;

do{

ch = (char) x;

System.out.print(ch + " ");

if (x % 10 == 0)

break;

++x;

} while (x <= 100);

Ans: a b c d

(i) Write the java expression for: [2]

Ans: - (double) (Math.pow(a, 2) + Math.pow(b, 2)) / (2 * a * b)

(j) If int y = 10 then find int z = (++y * (y++ + 5)); [2]

Ans: 176

SECTION – B (60 MARKS)

Attempt any four questions

Question 4:

Define a class ParkingLot with the following description: [15]

Instance variables / Data members:

int vno – To store the vehicle number

int hours – To store the number of hours the vehicle is parked in the parking lot

double bill – To store the bill amount

Member methods:

void input() – To input and store vno and hours

void calculate() – To compute the parking charge at the rate of Rs.3 for the first hour or part thereof, and Rs.1.50 for each additional hour or part thereof.

void display() – To display the detail

Write a main method to create an object of the class and call the above methods.

Ans:

import java.util.*;

class ParkingLot {

private int vno; private int hours; private double bill;

public void input() {

Scanner sc = new Scanner(System.in); System.out.print("Enter vehicle number: "); vno = sc.nextInt();

System.out.print("Enter hours: "); hours = sc.nextInt();

}

public void calculate() {

bill = 3 + (hours - 1) * 1.50;

}

public void display() {

System.out.println("Vehicle number: " + vno); System.out.println("Hours: " + hours); System.out.println("Bill: Rs. " + bill);

}

public static void main() {

ParkingLot ob = new ParkingLot(); ob.input();

ob.calculate(); ob.display();

}

Question 5:

Write two separate programs to generate the following patterns using iteration(loop) statements: [15]

(a)

* #

* # *

* # * #

* # * # *

(b) To display the following pattern:

5 4 3 2 1

5 4 3 2

5 4 3

5 4

Ans: -

(a)

class Pattern1 {

public static void main() {

for (int i = 1; i <= 5; i++) {

for (int j = 1; j <= i; j++) {

if (j % n == 1)

System.out.print("* ");

else

System.out.print("# ");

}

System.out.println();

}

(b)

class Pattern2 {

public static void main()

{

int i, j;

for(i=1; i<=5; i++)

{

for(j=5; j>=i; j--)

System.out.print(j);

System.out.println();

}

Question 6:

Write a program in to input and store all roll numbers, names and marks in 3 subjects of n number of students in five single dimensional arrays and display the remark based on average marks as given below: [15]

Average marks = total marks / 3

Average Marks	Remarks
85 – 100	EXCELLENT
75 – 84	DISTINCTION
60 – 74	FIRST CLASS
40 – 59	PASS
LESS THAN 40	POOR

Ans:

import java.util.Scanner; public class Marks {

public static void main() {

Scanner sc = new Scanner(System.in);

System.out.print("Enter number of students: ");

int n = sc.nextInt();

int[] rollNumbers = new int[n];

String[] names = new String[n];

int[] subject1Marks = new int[n];

int[] subject2Marks = new int[n];

int[] subject3Marks = new int[n];

for (int i = 0; i < n; i++) {

System.out.println("Student " + (i + 1));

System.out.print("Enter roll number: ");

rollNumbers[i] = sc.nextInt();

System.out.print("Enter name: ");

names[i] = sc.nextLine();

System.out.print("Enter marks in subject 1: ");

subject1Marks[i] = sc.nextInt();

System.out.print("Enter marks in subject 2: ");

subject2Marks[i] = sc.nextInt();

System.out.print("Enter marks in subject 3: ");

subject3Marks[i] = sc.nextInt();

}

for (int i = 0; i < n; i++) {

System.out.println("Roll number = " + rollNumbers[i] + ", Name= " + names[i]);

int averageMarks = (subject1Marks[i] + subject2Marks[i] + subject3Marks[i]) / 3;

if (averageMarks >= 85 && averageMarks <= 100) { System.out.println("EXCELLENT");
} else if (averageMarks >= 75 && averageMarks <= 84) { System.out.println("DISTINCTION");
} else if (averageMarks >= 60 && averageMarks <= 74) { System.out.println("FIRST CLASS");
} else if (averageMarks >= 40 && averageMarks <= 59) { System.out.println("PASS");

} else if (averageMarks < 40) {

System.out.println("POOR");

}

Question 7:

Design a class to overload a function Joystring() as follows: [15]

(i) void Joystring(String s, char ch1, char ch2) with one string and two character arguments that replaces the character argument ch1 with the character argument ch2 in the given string s and prints the new string

Example:

Input value of s = "TECHNALAGY"

ch1 = 'A'

ch2 = 'O'

Output : "TECHNOLOGY"

(ii) void Joystring(String s) with one string argument that prints the position of the first space and the last space of the given String s.

Example:

Input value of s = "Cloud computing means Internet based computing"

First Index: 5

Last Index: 36

(iii) void Joystring(String s1, String s2) with two string arguments that combines the two strings with a space between them and prints the resultant string

Example:

Input value of s1 = "COMMON WEALTH"

s2 = "GAMES"

Output: COMMON WEALTH GAMES

(use library functions)

Ans:

import java.util.Scanner;

class StringOperations {

public void Joystring(String s, char ch1, char ch2) { String output = s.replace(ch1, ch2); System.out.println("Output = " + output);

}

public void Joystring(String s) {

int firstIndexOfSpace = s.indexOf(' '); int lastIndexOfSpace = s.lastIndexOf(' ');

System.out.println("First index of space = " + firstIndexOfSpace); System.out.println("Last index of space = " + lastIndexOfSpace);

}

public void Joystring(String s1, String s2) {

String output = s1.concat(" ").concat(s2); System.out.println("Output = " + output);

}

Question 8:

Write a program to input twenty names in an array. Arrange these names in descending order of alphabets , using the bubble sort technique. [15]

Ans:

import java.util.Scanner;

public class SortNames {

public static void main() {

Scanner sc = new Scanner(System.in);

String[] names = new String[20];

System.out.println("Enter 20 names");

for (int i = 0; i < 20; i++)

names[i] = sc.nextLine();

for (int i = 0; i < names.length; i++) {

for (int j = 1; j < (names.length - i); j++) {

if (names[j - 1].compareTo(names[j]) > 0) {

String temp = names[j - 1];

names[j - 1] = names[j];

names[j] = temp;

}

System.out.println("Sorted names: ");

for (int i = 0; i < names.length; i++)

System.out.println(names[i]);

}

Question 9:

Use switch statement, write a menu driven program to: [15]

(i) To find and display all the factors of a number input by the user (including 1 and excluding number itself.)

Example:

Sample Input: n = 15

Sample Output: 1, 3, 5

(ii) To find and display the factorial of a number input by the user. The factorial of a non-negative integer n, denoted by n!, is the product of all integers less than or equal to n.

Example:

Sample Input: n = 5

Sample Output: 120

For an incorrect choice, an appropriate error message should be displayed.

Ans: -

import java.util.*;

public class Menu

{

public static void main()

{

Scanner sc = new Scanner(System.in);

System.out.println("1. Factors");

System.out.println("2. Factorial");

System.out.print("Enter your choice: ");

int ch = sc.nextInt();

switch(ch){

case 1:

System.out.print("Enter n: ");

int n = sc.nextInt();

for (int i = 1; i < n; i++) {

if (n % i == 0)

System.out.println(i);

}

break;

case 2:

System.out.print("Enter n: ");

int n = sc.nextInt();

int factorial = 1;

for (int i = 1; i < n; i++)

factorial = factorial * i;

System.out.println("Factorial: " + factorial);

break;

default:

System.out.println("Invalid choice");

}

ICSE Solved Paper, 2016

2020-11-21T14:00:00.003+05:30

ICSE Examination 2016 – 17 (Solution)

COMPUTER APPLICATION
Class – X
SECTION – A (40 MARKS)
Attempt all questions

Question 1:

(a) Define Encapsulation. [2]

Ans: - Encapsulation is the process of wrapping up of data and associated methods into a single unit (class).

(b) What are keywords? Give an example. [2]

Ans: - Keywords are reserved words which convey special meaning to the compiler. They cannot be used as identifiers. For example, class, void, etc.

(c) Name any tow library packages. [2]

Ans: - i) java.util

ii) java.io

(d) Name the type of error (Syntax, runtime or logical error) in each case given below:

(i) Math.sqrt(35 – 45);

(ii) int a;b;c; [2]

Ans: - i) Runtime error, because Math.sqrt(– 9) which cannot be computed as square root of a negative number is not defined.

ii) Syntax error, because multiple variables can be defined in one of the following ways: int a, b, c; int a; int b; int c;

(e) If int x[] = {4, 3, 7, 8, 9, 10}; [2]

what are the values of p and q?

(i) p = x.length

(ii) q = x[2] + x[5] * x[1]

Ans: - i) 6

ii) q = x[2] + x[5] * x[1]

= 7 + 10 * 3

= 7 + 30

=37

Question 2:

(a) State the difference between = = and equals() method. [2]

Ans:

==	equals()
i) It is a relational operator.	i) It is a method of String class.
ii) It checks for equality of primitive types of values.	ii) It checks for equality of two String type of values.

(b) What are the types of casting shown by the following examples: [2]

(i) char c = (char) 120;

(ii) int x = 't';

Ans: - i) Explicit casting

ii) Implicit casting

(c) Differentiate between formal parameter and actual parameter. [2]

Ans: - Formal parameters are the parameters defined in the signature of a method. Actual parameters are values given to the method at the time of method call.

(d) Write the function prototype of the following: [2]

A function PosChar which takes a String argument and a character argument and returns an integer value.

Ans: - int PosChar(String s, char c)

(e) Name any two types of access specifiers. [2]

Ans: - public, private, protected and default (any two out of these 4).

Question 3:

(a) Give the output of the following String function: [2]

(i) “MISSISSIPPI”.indexOf('S') + “MISSISSIPPI”.lastIndexOf('I')

(ii) “CABLE”.compareTo(“CADET”)

Ans: - i) 2 + 10 = 12

ii) 66 – 68 = – 2

(b) Give the output of the following Math functions: [2]

(i) Math.ceil (4 . 2)

(ii) Math.abs (– 4)

Ans: - i) 5.0

ii) 4

(c) What is parameterized constructor? [2]

Ans: - A parameterized constructor is a constructor that accepts arguments which are used to initialize the object being created.

(d) Write down Java expression for: [2]

Ans: - double T = Math.sqrt(Math.pow(a, 2) + Math.pow(b, 2) + Math.pow(c, 2));

OR,

double T = Math.sqrt((A*A) + (B*B) + (C*C));

(e) Rewrite the following using ternary operator: [2]

if(x%2 == 0)

System.out.print("EVEN");

else

System.out.print("ODD");

Ans: - System.out.println(x % 2 == 0 ? “EVEN” : “ODD”);

(f) Convert the following while loop to the corresponding for loop: [2]

int m = 5, n = 10;

while (n>=1)

{

System.out.println(m*n); n–-;

}

Ans: - for(int m=5, n=10; n >=1; n--)

System.out.println(m*n);

(g) Write one difference between primitive data types and composite data types. [2]

Ans: - A primitive data types are predefined or inbuilt data types. For example, int, double, etc.

Composite data types are defined by user and made-up of primitive data types values. For example, class, array.

(h) Analyze the given program segment and answer the following questions: [2]

(i) Write the output of the program segment

(ii) How many times does the body of the loop gets executed?

for(int m=5; m<=20; m+=5)

{

if(m%3 == 0)

break;

else if(m%5 == 0)

System.out.println(m);

continue;

}

Ans: - i) 5

ii) 3 times

(i) Write the return type of the following library functions: [2]

(i) isLetterOrDigit(char)

(ii) replace(char, char)

Ans: - i) boolean

ii) String

SECTION – B (60 MARKS)

Attempt any four questions

Question 4:

Define a class named BookFair with the following description: [15]

Instance variables / Data members:

String Bname – stores the name of the book

double price – stores the price of the book

Member methods:

(i) BookFair() – default constructor to initialize data members (

ii) void Input() – To input and store the name and price of the book

(iii) void calculate() – To calculate the price after discount. Discount is calculated based on the following criteria.

Price	Discount
Less than or equal to ₹ 1000	2% of price
More than ₹ 1000 and less than or equal to ₹ 3000	10% of price
More than ₹ 3000	15% of price

(iv) void display() – To display the name and price of the book after discount.

Write a main method to create an object of the class and call the above member methods.

Ans: -

import java.util.*;

public class BookFair

{

String Bname;

double price;

BookFair()

{

Bname = null;

price = 0.0;

}

void Input()

{

Scanner sc = new Scanner(System.in);

System.out.print("Enter book name: ");

Bname = sc.nextLine();

System.out.print("Enter price: ");

price = sc.nextDouble();

}

void calculate()

{

double discountPercentage = 0;

if (price <= 1000)

discountPercentage = 2;

else if (price <= 3000)

discountPercentage = 10;

else if (price > 3000)

discountPercentage = 15;

price = price - (price * discountPercentage / 100);

}

void display()

{

System.out.println("Name: " + Bname);

System.out.println("Price after discount: " + price);

}

public static void main()

{

BookFair ob = new BookFair();

ob.Input();

ob.calculate();

ob.display();

}

Question 5:

Using the switch statement, write a menu driven program for the following: [15]

(i) To print the Floyd‟s triangle [Given below]

2 3

4 5 6

7 8 9 10

11 12 13 14 15

(ii) To display the following pattern:

I C

I C S

I C S E

For an incorrect option, an appropriate error message should be displayed. [15]

Ans: -

import java.util.*;

public class Menu

{

public static void main()

{

Scanner sc = new Scanner(System.in);

System.out.println("1. Floyd's triangle");

System.out.println("2. ICSE Pattern");

System.out.print("Enter your choice: ");

int ch = sc.nextInt();

switch (ch)

{

case 1:

System.out.print("Enter n (number of lines): ");

int n = sc.nextInt();

int currentNumber = 1;

for (int i = 1; i <= n; i++)

{

for (int j = 1; j <= i; j++)

{

System.out.print(currentNumber + " ");

currentNumber++;

}

System.out.println();

}

break;

case 2:

System.out.print("Enter word: ");

String word = sc.next();

for (int i = 0; i < word.length(); i++)

{

for (int j = 0; j <= i; j++)

System.out.print(word.charAt(j) + " ");

System.out.println();

}

break;

default:

System.out.println("Invalid choice");

break;

}

Question 6:

Special words are those words which start and end with the same letter.

Examples:

EXISTENCE

COMIC

WINDOW

Palindrome words are those words which read the same from left to right and viceversa.

Examples:

MALAYALAM

MADAM

LEVEL

ROTATOR

CIVIC

All palindromes are special words, but all special words are not palindromes. Write a program to accept a word to check and print whether the word is a palindrome or only special word. [15]

Ans:

class Words

{

public static void main(String s)

{

String reverse = "";

for (int i = s.length() - 1; i >= 0; i--)

reverse = reverse + s.charAt(i);

if (s.equals(reverse))

System.out.println("Palindrome");

char firstLetter = s.charAt(0);

char lastLetter = s.charAt(s.length() - 1);

if (firstLetter == lastLetter)

System.out.println("Special word");

}

Question 7:

Design a class to overload a function SumSeries() as follows: [15]

(i) void SumSeries(int n, double x) – with one integer argument and one double argument to find and display the sum of the series given below:

(ii) void SumSeries() – to find and display the sum of the following series: s = 1 + (1×2) + (1×2×3) + …. + (1×2×3×4× …. 20)

Ans: -

class Series

{

void SumSeries(int n, double x)

{

double sum = 0;

for (int i = 1; i <= n; i++)

{

if (i % 2 == 1)

sum = sum + (x / i);

else

sum = sum - (x / i);

}

System.out.println("Sum = " + sum);

}

void SumSeries()

{

int sum = 0;

for (int i = 1; i <= 20; i++)

{

int product = 1;

for (int j = 1; j <= i; j++)

product = product * j;

sum = sum + product;

}

System.out.println("Sum = " + sum);

}

Question 8:

Write a program to accept a number and check and display whether it is a Niven number or not. [15]

(Niven number is that number which is divisible by its sum of digits)

Example:

Consider the number 126

Sum of its digits is 1 + 2 + 6 = 9 and 126 is divisible by 9.

Ans: -

class NivenNumber

{

public static void main(int n)

{

int sumOfDigits = 0;

int copyOfNum = n;

while (n > 0)

{

int remainder = n % 10;

n = n / 10;

sumOfDigits = sumOfDigits + remainder;

}

if (copyOfNum % sumOfDigits == 0)

System.out.println("Niven number");

else

System.out.println("Not a niven number");

}

Question 9:

Write a program to initialize the seven Wonders of the World along with their locations in two different arrays. Search for a name of the country input by the user. If found, display the name of the country along with its Wonder, otherwise display “Sorry Not Found!” [15]

Seven wonders – CHICHEN ITZA, CHRIST THE RDEEEMER, TAJMAHAL, GREAT WALL OF CHINA, MACHU PICCHU, PETRA, COLOSSEUM

Locations – MEXICO, BRAZIL, INDIA, CHINA, PERU, JORDAN, ITALY

Example – Country Name: INDIA

Output: INDIA – TAJMAHAL

Country Name: USA

Output: Sorry Not Found!

Ans: -

import java.util.*;

public class SevenWonders

{

public static void main()

{

String[] sevenWonders = { "CHICHEN ITZA", "CHRIST THE RDEEEMER", "TAJMAHAL", "GREAT WALL OF CHINA", "MACHU PICCHU", "PETRA", "COLOSSEUM" };

String[] locations = { "MEXICO", "BRAZIL", "INDIA", "CHINA", "PERU", "JORDAN", "ITALY" };

Scanner sc = new Scanner(System.in);

System.out.print("Enter country: ");

String country = sc.next();

int index = -1;

for (int i = 0; i < locations.length; i++)

{

if (locations[i].equals(country))

index = i;

}

if (index != -1)

System.out.println(locations[index] + " - " + sevenWonders[index]);

else

System.out.println("Sorry Not Found!");

}

ICSE Solved Paper, 2017

2020-11-19T10:54:00.003+05:30

ICSE Examination 2017 – 18 (Solution)

COMPUTER APPLICATION
Class – X
SECTION – A (40 MARKS)
Attempt all questions

Question 1:

(a) What is Inheritance? [2]

Ans: - Inheritance is the process by which one class extends another class to inherit the variables and functions and add any additional variables and methods.

(b) Name the operators listed below: [2]

i) <

ii) ++

iii) &&

iv)? :

Ans: - i) < – Less than relational operator

ii) ++ – increment operator

iii) && – Logical AND operator

iv) ? : – Ternary operator

(c) State the number of bytes occupied by char and int data types. [2]

Ans: - char occupies two bytes and int occupies 4 bytes.

(d) Writ one difference between / and % operator. [2]

Ans: - / division operator which gives quotient while % is modules operator which gives the remainder on dividing two numbers.

(e) String x[] = {“SAMSUNG”, “NOKIA”, “SONY”, “MICROMAX”, “BLAKBERRY”}; [2]

Give the output of the following statements:

i) System.out.println(x[1]);

ii) System.out.println(x[3].length());

Ans: - i) NOKIA

ii) “MICROMAX”.length()

= 8

Question 2:

(a) Name of the following:

i) A keyword used to call a package in the program.

ii) Any one reference data types.

Ans: - i) import

ii) String

(b) What are the two ways of invoking functions? [2]

Ans: - Call by value and Call by reference

(c) State the data type and value of res after the following is executed:

char ch = 't';

res = Character.toUpperCase(ch); [2]

Ans: - Data type of res is char and value is T

(d) Give the output of the following program segment and also mention the number of times the loop is executed: [2]

int a,b;

for(a=6,b=4;a<=24;a=a+6)

{

if(a%b==0)

break;

}

System.out.println(a);

Ans: - The output is 12 and loop is executed 2 times.

(e) Write the output: [2]

char ch= 'F';

int m=ch;

m=m+5;

System.out.println(m+ " " +ch);

Ans: - 75 F

Question 3:

(a) Write a Java expression for the following: [2]

Ans: - a * Math.pow(x, 5) + b *b Math.pow(x, 3) + c

(b) What is the value of x1 if x = 5? [2]

x1 = ++x – x++ + – –x

Ans: x1 = ++x – x++ + – –x

x1 = 6 – 6 + 6

x1 = 6

(c) Why is an object called an instance of a class? [2]

Ans: - An object is called an instance of a class as every object created from a class gets its own instances of the variables defined in the class. Multiple objects can be created from the same class.

(d) Convert following do-while loop into for loop. [2]

int i=1;

int d=5;

do{

d=d*2;

System.out.println(d);

i++;

}while(i<=5);

Ans: for(int i=1, d=5; i<=5; i++)

{

d = d * 2;

System.out.println(d);

}

(e) Differentiate between constructor and function. [2]

Ans: - (i) The constructor of a class is invoked automatically during object creation while a function is invoked manually after object creation.

(ii)A constructor is invoked only once while a function can be invoked multiple times.

(iii) A constructor has the same name as the class in which it is defined while a function can have any time.

(f) Write the output of the following: [2]

String s= "Today is Test";

System.out.println(s.indexOf('T'));

System.out.println(s.substring(0,7)+ " "+ "Holiday");

Ans: - 0

Today i Holiday

(g) What are the values stored in variables r1 and r2: [2]

i) double r1 = Math.abs(Math.min(–2.83, –5.83));

ii) double r2 = Math.sqrt(Math.floor(16.3));

Ans: - i) 5.83

ii) 4.0

(h) Give the output of the following code: [2]

String A= "26", B= "100" ;

String D=A+B+ "200";

int x= Integer.parseInt(A);

int y=Integer.parseInt(B);

int d=x+y;

System.out.println("Result 1=" +D);

System.out.println("Result 2="+d);

Ans: - Result 1 = 26100200

Result 2 = 126

(i) Analyze the given program segment and answer the following questions: [2]

for(int i=3;i<=4;i++){

for(int j=2;j<i;j++){

System.out.print(" ");

}

System.out.println("WIN");

}

(i) How many times does the inner loop execute?

(ii) Write the output of the program segment.

Ans: - i) 3 times

ii) WIN

WIN

(j) What is the difference between the Scanner class functions next() and nextLine()? [2]

Ans: - next() read a single token i.e. all characters from the current position till a whitespace

or tab or new line is encountered.

nextLine() reads an entire line i.e. all characters from the current position till a new

line is encountered.

SECTION – B (60 MARKS)

Attempt any four questions

Question 4:

Define a class ElectricBill with the following specifications:

class : ElectricBill

Instance variable / data members

String n – to store the name of the customer

int units – to store the number of units consumed

double bill – to store the amount to be paid

Methods

void accept(): to accept the name of the customer and number of units consumed.

void calculate(): to calculate the bill as per the following tariff:

Number of units Rate per unit

First 100 units ₹ 2.00

Next 200 units ₹ 3.00

Above 300 units ₹ 5.00

A surcharged of 2.5% charged if the number of units consumed is above 300 units.

void print(): to print the details as follows:

Name of the customer: ___________

Number of units consumed: ________

Bill amount: __________

Write a main() method to create an object of the class and call the above member functions. [15]

Ans: -

import java.util.*;

class ElectricBill

{

private String n;

private int units;

private double bill;

void accept()

{

Scanner sc = new Scanner(System.in);

System.out.print("Enter name: ");

n = sc.next();

System.out.print("Enter units: ");

units = sc.nextInt();

}

void calculate()

{

if (units <= 100)

bill = units * 2;

else if (units <= 300)

bill = 100 * 2 + (units - 100) * 3;

else

{

bill = 100 * 2 + 200 * 3 + (units - 300) * 5;

double surcharge = bill * 2.5 / 100;

bill = bill + surcharge;

}

public void print()

{

System.out.println("Name of the customer: " + n);

System.out.println("Number of units consumed: " + units);

System.out.println("Bill amount: " + bill);

}

public static void main()

{

ElectricBill ob= new ElectricBill();

ob.accept();

ob.calculate();

ob.print();

}

Question 5:

Write a program to accept a number and check and display whether it is a spy number or not. [15]

A number is spy if the sum of its digits equals the product of its digits.

Example: Consider the number 1124

Sum of the digits = 1 + 1 + 2 + 4 = 8

Product of the digits = 1 × 1 × 2 × 4 = 8

Ans: -

class SpyNumber

{

public static void main(int n)

{

int sumOfDigits = 0;

int productOfDigits = 1;

while (n > 0)

{

int remainder = n % 10;

sumOfDigits = sumOfDigits + remainder;

productOfDigits = productOfDigits * remainder;

n = n / 10;

}

if (sumOfDigits == productOfDigits)

System.out.println("Spy number");

else

System.out.println("Not a spy number");

}

Question 6:

Using switch statement, write a menu driven program for the following: [15]

i) To find and display the sum of the series given below:

ii) To display the following series:

1 11 111 1111 11111

For an incorrect option, an appropriate error message should displayed.

Ans: -

import java.util.*;

class Menu

{

public static void main()

{

System.out.println("1. Sum of series");

System.out.println("2. Display Series");

System.out.print("Enter your choice: ");

Scanner sc = new Scanner(System.in);

int choice = sc.nextInt();

switch (choice)

{

case 1:

double sum = 0;

for (int i = 1; i <= 20; i++)

{

if (i % 2 == 1)

sum = sum + Math.pow(2, i);

else

sum = sum - Math.pow(2, i);

}

System.out.println("Sum = " + sum);

break;

case 2:

for (int i = 1; i <= 5; i++)

{

for (int j = 1; j <= i; j++)

System.out.print("1");

System.out.print(" ");

}

break;

default:

System.out.println("Invalid choice");

}

Question 7:

Write a program to input integer elements into an array of size 20 and perform the following operations: [15]

i) Display largest number from the array

ii) Display smallest number from the array

iii) Display sum of all the elements of the array

Ans: -

import java.util.*;

class ArrayOperations

{

public static void main()

{

Scanner sc = new Scanner(System.in);

int[] numbers = new int[20];

System.out.print("Enter 20 numbers: ");

for (int i = 0; i < 20; i++)

numbers[i] = sc.nextInt();

int smallest = numbers[0];

int largest = numbers[0];

int sum = 0;

for (int i = 0; i < 20; i++)

{

if (numbers[i] < smallest)

smallest = numbers[i];

if (numbers[i] > largest)

largest = numbers[i];

sum = sum + numbers[i];

}

System.out.println("Smallest = " + smallest);

System.out.println("Largest = " + largest);

System.out.println("Sum = " + sum);

}

Question 8:

Design a class to overload a function check() as follows: [15]

i) void check(String str, char ch) – to find and print the frequency of a character in a String.

Example:

str = “success”;

ch = 's';

Output: Number of s present is = 3

ii) void check(String s1) – to display only the vowels from string s1, after converting it to lower case.

Example:

s1 = “computer”;

Output – o u e

Ans: -

class Overload

{

public void check(String str, char ch)

{

int result = 0;

for (int i = 0; i < str.length(); i++)

{

char currentChar = str.charAt(i);

if (ch == currentChar)

result++;

}

System.out.println("number of s present is = " + result);

}

public void check(String s1)

{

s1 = s1.toLowerCase();

for (int i = 0; i < s1.length(); i++)

{

char currentChar = s1.charAt(i);

if (currentChar == 'a' || currentChar == 'e' || currentChar == 'i' || currentChar == 'o' || currentChar == 'u')

System.out.print(currentChar + " " );

}

Question 9:

Write a program to input forty words in an array. Arrange these words in descending order of alphabets, using selection sort technique. Print the sorted array. [15]

Ans: -

import java.util.*;

class SelectionSort

{

public static void main()

{

Scanner sc = new Scanner(System.in);

String[] words = new String[40];

System.out.println("Enter 40 words: ");

for (int i = 0; i < 40; i++)

words[i] = sc.nextLine();

for (int i = 0; i < words.length - 1; i++)

{

int largestWordIndex = i;

for (int j = i + 1; j < words.length; j++)

{

if (words[j].compareTo(words[largestWordIndex]) > 0)

largestWordIndex = j;

}

String temp = words[largestWordIndex];

words[largestWordIndex] = words[i];

words[i] = temp;

}

for (int i = 0; i < 40; i++)

System.out.println(words[i]);

}

ICSE Solved Paper, 2018

2020-11-13T12:29:00.018+05:30

ICSE Examination 2018 – 19 (Solution)

COMPUTER APPLICATION
Class – X
SECTION – A (40 MARKS)
Attempt all questions

Question 1:

(a) Define Abstraction. [2]

Ans: - Abstraction refers to specifying the behavior of a class without going into the details of the implementation.

(b) Differentiate between searching and sorting. [2]

Ans: - In searching, we are provided with an array which contains multiple elements and asked to find the index of a specific element. In sorting, an array is provided and we are asked to order the elements in either ascending or descending order.

(c) Write a difference between the functions isUpperCase() and toUpperCase(). [2]

Ans: - isUpperCase() returns the boolean value whereas, toUpperCase returns character value.

(d) How are private members of a class different from public members? [2]

Ans: - Private members of a class can be accessed only by the methods of the class in which they are declared. While public members can be accessed outside of the class also.

(e) Classify the following as primitive or non-primitive data types: [2]

Ans: - char – Primitive

arrays – Non-primitive

int – Primitive

classes – Non-primitive

Question 2:

(a) (i) int res = 'A';

What is the value of res?

(ii) Name the package that contains wrapper classes. [2]

Ans: - (i) res = 65

(ii) java.lang package contains wrapper classes.

(b) State the difference between while and do-while loop. [2]

Ans: - A while is an entry controlled loop i.e. the loop condition is checked before the loop is executed while, do-while is an exit controlled loop i.e. the loop condition is checked after the loop is executed.

(c) System.out.print(“BEST ”);

System.out.print(“OF LUCK ”);

Choose the correct option for the output of the above statements: [2]

(i) BEST OF LUCK

(ii) BEST

OF LUCK

Ans: - (i) BEST OF LUCK is the correct answer.

(d) Write the prototype of a function check which takes an integer as an argument and returns a character. [2]

Ans: - char function(int a)

(e) Write the return data type of the following functions: [2]

(i) endsWith()

(ii) log()

Ans: - (i) endsWith – boolean

(ii) log() – double

Question 3:

(a) Write a Java expression for the following: [2]

Ans: Math•sqrt(3 * x + Math•pow(x, 2)) / (a + b);

(b) What is the value of y after evaluating the expressing given below? [2]

y+= ++y + y– + – –y; when int y=8.

Ans: - y+= ++y + y– – + – –y

8 + 9 + 9 + 7

y=33

(c) Give the output of the following: [2]

(i) Math.floor(–4.7)

(ii) Math.ceil(3.4) + Math.pow(2,3)

Ans: - i) – 5.0

ii) 4.0 + 8.0

= 12.0

(d) Write two characteristics of a constructor. [2]

Ans: - i) A constructor has the same name as that of the class.

ii) A constructor does not have a return type.

(e) Write the output of the following: [2]

System.out.println(“Incredible” + “\n” + “world”);

Ans: - Incredible

world

(f) Convert the following if else if constructor into switch case: [2]

if(var = = 1)

System.out.println("good");

else if(var = = 2)

System.out.println("better");

else if(var = = 3)

System.out.println("best");

else

System.out.println("invalid");

Ans: - switch(var)

{

case 1:

System.out.println("good");

break;

case 2:

System.out.println("better");

break;

case 3:

System.out.println("best");

break;

default:

System.out.println("invalid");

}

(g) Give the output of the following String functions: [2]

(i) “ACHIEVEMENT”.replace(„E‟, „A‟)

(ii) “DEDICATED”.compareTo(“DEVOTE”)

Ans: - i) ACHIAVAMANT

ii) D – V = 68 – 86 = – 18

(h) Consider the following String array and give the output: [2]

String arr[] = {"DELHI", "CHENNAI", "MUMBAI", "LUCKNOW", "JAIPUR"};

System.out.println(arr[0].length() > arr[3].length());

System.out.print(arr[4].substring(0, 3));

Ans: - arr[0].length() > arr[3].length()

= “DELHI”.length() > “LUCKNOW”.length()

= 5 > 7

So, output is false

arr[4].substring(0, 3)

JAIPUR.substring(0, 3)

So, output is JAI

(i) Rewrite the following using ternary operator: [2]

if(bill > 10000)

discount = bill * 10.0 / 100;

else

discount = bill * 5.0 / 100;

Ans: discount = bill > 10000 ? (bill * 10.0 / 100) : (bill * 5.0 / 100);

(j) Give the output of the following program segment and also mention how many times the loop is executed: [2]

int i;

for(i = 5; i > 10; i++)

System.out.println(i);

System.out.println(i * 4);

Ans: Loop condition i>10 i.e. 5>10 which is false. So, loop is not executed even once.

Output will be 5 * 4 =20

SECTION – B (60 MARKS)

Attempt any four questions

Question 4:

Design a class RailwayTicket with following description:

Instance Variable / Data members

String name : to store the name of the customer

String coach : to store the type of coach customer wants to travel

long mobno : to store customer‟s mobile number

int amt : to store basic amount of ticket

int totalamt : to store the amount to be paid after updating the original amount

Methods:

void accept() : to take input for name, coach, mobile number and amount

void update() : to update the amount as per the coach selected.

Extra amount to be added in the amount as follows:

Type of coaches Amount

First_AC 700

Second_AC 500

Third_AC 250

sleeper None

void display() : To display all details of a customer such as name, coach, total amount and mobile number.

Write a main() method to create an object of the class and call the above methods. [15]

Ans:

import java.util.*;

class RailwayTicket

{

String name;

String coach;

long mobno;

int amt;

int totalamt;

void accept()

{

Scanner sc = new Scanner(System.in);

System.out.print("Enter name: ");

name = sc.nextLine();

System.out.print("Enter coach: ");

coach = sc.nextLine();

System.out.print("Enter mobno: ");

mobno = sc.nextLong();

System.out.print("Enter amt: ");

amt = sc.nextInt();

}

void update()

{

if (coach.equals("First_AC"))

totalamt = amt + 700;

else if (coach.equals("Second_AC"))

totalamt = amt + 500;

else if (coach.equals("Third_AC"))

totalamt = amt + 250;

else if (coach.equals("sleeper"))

totalamt = amt;

}

void display()

{

System.out.println("Name: " + name);

System.out.println("Coach: " + coach);

System.out.println("Mobile Number: " + mobno);

System.out.println("Amount: " + amt);

System.out.println("Total Amount: " + totalamt);

}

public static void main()

{

RailwayTicket ob= new RailwayTicket();

ob.accept();

ob.update();

ob.display();

}

Question 5:

Write a program to input a number and check and print whether it is a Pronic number or not. Pronic number is the number which is the product of two consecutive integers. [15]

Examples:

12 = 3 × 4

20 = 4 × 5

42 = 6 × 7

Ans: -

class PronicNumber

{

public static void main(int n)

{

boolean pronic = false;

for (int i = 1; i < n; i++)

{

int product = i * (i + 1);

if (product = = n)

{

pronic = true;

break;

}

System.out.println("Pronic number = " + pronic);

}

Question 6:

Write a program in Java to accept a string in lowercase and change the first letter of every word to uppercase. Display the new string. [15]

Sample INPUT : we are in cyber world

Sample OUTPUT : We Are In Cyber World

Ans:

class SentenceCase

{

public static void main(String s)

{

String output = "";

for (int i = 0; i < s.length(); i++)

{

char ch = s.charAt(i);

if (i = = 0 || s.charAt(i - 1) = = ' ')

output = output + Character.toUpperCase(ch);

else

output = output + ch;

}

System.out.println("Output: " + output);

}

Question 7:

Design a class to overload a function volume() as follows:

(i) double volume(double r) – with radius 'r' as an argument, returns the volume of sphere using the formula:

(ii) double volume(double h, double r) – with height 'h' and radius 'r' as the arguments. returns the volume of a cylinder using the formula:

(iii) double volume(double l, double b, double h) – with length 'l', breadth 'b' and height 'h' as the arguments, returns the volume of a cuboid using the formula:

v = l × b × h

Ans:

class Overload

{

double volume(double r)

{

double vol = 4.0 / 3 * 22 / 7 * Math.pow(r, 3);

return vol;

}

double volume(double h, double r)

{

double v = 22.0 / 7 * Math.pow(r, 2) * h;

return v;

}

double volume(double l, double b, double h)

{

double v = l * b * h;

return v;

}

Question 8:

Write a menu driven program to display the pattern as per user's choice: [15]

Pattern 1 Pattern 2

ABCDE B

ABCD LL

ABC UUU

AB EEEE

For an incorrect option, an appropriate error message should be displayed.

Ans:

import java.util.Scanner;

class Pattern

{

public static void main()

{

Scanner sc = new Scanner(System.in);

System.out.print("1. Pattern 1");

System.out.print("2. Pattern 2");

System.out.print("Enter your choice: ");

int ch = sc.nextInt();

switch(ch)

{

case 1:

System.out.print("Enter number of lines: ");

int n = sc.nextInt();

for (int i = n; i >= 1; i--)

{

for (int j = 0; j < i; j++)

System.out.print((char) ('A' + j));

System.out.println();

}

break;

case 2:

System.out.print("Enter string: ");

String s = sc.next();

char ch;

for (int i = 0; i < s.length(); i++)

{

ch = s.charAt(i);

for (int j = 1; j <= (i + 1); j++)

System.out.print(ch);

System.out.println();

}

break;

default:

System.out.println("Invalid choice");

}

Question 9:

Write a program to accept name and total marks of N number of students in two single subscripts array name[] and totalmarks[]. [15]

Calculate and print:

(i) The average of the total marks obtained by N number of students. [average = (sum of total marks of all the students) / N]

(ii) Deviation of each student‟s total marks with the average. [deviation = total marks of a student – average]

Ans:

import java.util.*;

class Student

{

public static void main()

{

Scanner sc = new Scanner(System.in);

System.out.print("Enter number of students: ");

int n = sc.nextInt();

String[] name = new String[n];

int[] totalmarks = new int[n];

for (int i = 0; i < n; i++)

{

System.out.println("Student " + (i + 1));

System.out.print("Enter name: ");

name[i] = sc.next();

System.out.print("Enter marks: ");

totalmarks[i] = sc.nextInt();

}

int sum = 0;

for (int i = 0; i < n; i++)

sum = sum + totalmarks[i];

double average = (double) sum / n;

System.out.println("Average is " + average);

for (int i = 0; i < n; i++)

{

double deviation = totalmarks[i] - average;

System.out.println("Deviation of " + name[i] + " is " + deviation);

}

ICSE Solved Paper, 2019

2020-11-12T10:57:00.011+05:30

ICSE Examination 2019 – 20 (Solution)

COMPUTER APPLICATION
Class – X
Section – A (40 Marks)
Attempt all questions

Question 1:

a) Name any two basic principles of Object-oriented Programming. [2]
Ans: - Abstraction, Encapsulation, Inheritance and Polymorphism (Write any two).

b) Write a difference between unary and binary operator. [2]
Ans: - Unary operator works on single operand or variable. Binary operator works on two operands or variables.

c) Name the keyword which:
(i) indicates that a method has no return type.
(ii) makes the variable as a class variable. [2]
Ans: - (i) void (ii) static

d) Write the memory capacity (storage size) of short and float data type in bytes. [2]
Ans: - short – 2 bytes (16 bits), Float – 4 bytes (32 bits)

e) Identify and name the following tokens:
(i) public
(ii) "a"
(iii) = =
(iv) { } [2]
Ans: - (i) Keyword or Reserved word
(ii) Character constant or literal
(iii) Relational or comparison operator
(iv) separator or punctuator

Question 2:

(a) Differentiate between if else if and switch-case statement. [2]
Ans: - i) if else if allows all relational operators whereas, switch-case allows only = = operator.
ii) if else if allows all data types whereas switch-case allows int, char and String.
iii) Range of values are checked in if else if whereas, one value is compared.

(b) Give the output of the following code:
String P = “20”, Q = “19”;
int a = Ingeger.parseInt(P);
int b = Ingeger.parseInt(Q);
System.out.println(a+ “” +b); [2]
Ans: - 2019

(c) What are the various types of errors in Java? [2]
Ans: - i) Syntax error / Compiler time error
ii) Logical error
iii) Runtime error

(d) State the data type and value of res after the following is executed:
char ch = "9";
res = Character.isDigit(ch); [2]
Ans: - data type = boolean
res = true

(e) What is the difference between the linear search and the binary search technique? [2]
Ans: - Linear Search
i) Can work on unsorted array.
ii) Check each item.
iii) Takes more time.
Binary Search
i) Array must be sorted.
ii) Does not check each item.
iii) Takes less time

Question 3:

(a) Write a Java expression for the following: [2]

Ans: - Math.abs(x*x + 2*x*y) or, Math.abs(Math.pow(x,2) + 2*x*y);

(b) Write the return data type of the following functions: [2]
(i) startsWith()
(ii) random()
Ans: - startsWith() – Boolean
random() – double

(c) If the value of basic = 1500, what will be the value of tax after following statement is executed? tax = basic > 1200 ? 200 : 100; [2]
Ans: - tax = 200

(d) Give the output of the following code and mention how many times the loops will execute? [2]
int i;
for(i = 5; i>=1; i – –)
{
if(i%2 = = 1)
continue;
System.out.print(i+ “ ”);
}
Ans: - Output: 4 2
5 times the loop will execute.

(e) State a difference between call by value and call by reference. [2]

Call by value	Call by reference
i) It works with primitive data type.	i) It works with reference (address) data type.
ii) The original value of variable remains unchanged.	ii) The original value of variable changes.
iii) Operation is performed on duplicate value of variables.	iii) Operation is performed on original values of variables.
iv) It is also called pure function.	iv) It is also called as impure function.

(f) Give the output of the following: [2]
Math.sqrt(Math.max(9, 16))
Ans: - 4.0

(g) Write the output for the following: [2]
String s1 = “phoenix”;
String s2 = “island”;
System.out.println(s1.substring(0).concat(s2.substring(2)));
System.out.println(s2.toUpperCase());
Ans: phoenixland
ISLAND

(h) Evaluate the following expression if the value of x =2, y = 3 and z = 1. [2]
v = x+ – –z+ y++ +y;
Ans: v = 2 + 0 + 3 + 4 = 9

(i) String x[] = {“Artificial intelligence”, “IOT”, “Machine learning”, “Big data”}; [2]
Give the output of the following statements:
(i) System.out.println(x[3]);
(ii) System.out.println(x.length);
Ans: - i) Big Data
ii) 4

(j) What is meant by a package? Give an example. [2]
Ans: - Package is a group of related classes. Example: java.io, java.util, etc.

Section – B (60 Marks)
Attempt any four questions

Question 4:

Design a class name ShowRoom with the following description:

Instance variables / Data members:

String name - To store the name of the customer

long mobno - To store the mobile number of the customer

double cost - To store the cost of the items purchased

double dis - To store the discount amount

double amount - To store the amount to be paid after discount

Members methods:

ShowRoom() - default constructor to initialize data members

void input() - To input customer name, mobile number, cost

void calculate() - To calculate discount on the cost of purchased items, based on following criteria:

Cost	Discount (in percentage)
Less than or equal to ₹ 10000	5%
More than ₹ 10000 and less than or equal to ₹ 20000	10%
More than ₹ 20000 and less than or equal to ₹ 35000	15%
More than ₹ 35000	20%

void display() - To display customer name, mobile number, amount to be paid after discount

Write a main method to create an object of the class and call the above member methods. [15]

Ans:import java.util.*;

class ShowRoom

{

String name;

long mobno;

double cost, dis, amount;

ShowRoom()

{

name = “”;

cost = 0;

mobno = 0;

dis = 0.0;

amount = 0.0;

}

void input()

{

Scanner sc = new Scanner(System.in);

System.out.println(“Enter name, mobile no and cost”);

name = sc.next();

mobno = sc.nextLong();

cost = sc.nextDounle();

}

void calculate()

{

if(cost<=10000)

dis=0.05*cost;

else if(cost <= 20000)

dis = 0.1 * cost;

else if(cost <= 35000)

dis = 0.15 * cost;

else

dis = 0.2 * cost;

}

void display()

{

System.out.println(“Name is:”+name);

System.out.println(“Mobile no is:”+mobno);

System.out.println(“Amount is:”+amount);

}

public static void main()

{

ShowRoom ob = new ShowRoom();

ob.input();

ob.calculate();

ob.display();

}

Question 5:

Using the switch-case statement, write a menu driven program to do the following: [15]

(a) To generate and print Letters from A to Z and their Unicode

Letters Unicode

A 65

B 66

. .

Z 90

(b) Display the following pattern using iteration (looping) statement:

1 2

1 2 3

1 2 3 4

1 2 3 4 5

Ans: import java.util.*;

class MenuDriven

{

public static void main()

{

Scanner sc = new Scanner(System.in);

int ch, x;

System.out.println(“1. Unicode of letters”);

System.out.println(“2. Number pattern”);

System.out.println(“Enter your choice:”);

ch = sc.nextInt();

switch(ch)

{

case 1:

System.out.println(“Letters” + “\t” + “Unicode”);

for(char c=‟A‟; c<= „Z‟; c++)

{

x=c;

System.out.println(c+ “\t” + x);

}

break;

case 2:

for(int i =1; i<=5; i++)

{

for(j = 1; j<=i; j++)

System.out.print(j+ “\t”);

System.out.println();

}

break;

default:

System.out.println(“Wrong choice!”);

}

Question 6:

Write a program to input integer elements in an array and sort them in ascending order using the bubble sort technique. [15]

Ans: import java.util.*;

class BubbleSort

{

public static void main()

{

Scanner sc = new Scnanner(System.in);

int a[] = new int[15];

System.out.println(“Enter elements”);

for(int i = 0; i<15; i++) // OR i<a.length

a[i] = sc.nextInt();

int temp;

for(int i = 0; i<a.length – 1; i++) //OR i<14

{

for(int j=0; j<(a.length – 1) – i; j++) // OR j<14 – i

{

if(a[j] > a[j+1])

{

temp = a[j];

a[j] = a[j+1];

a[j+1] = temp;

}

for(int k = 0; k<a.length; k++) // OR k<15

System.out.println(a[k]);

}

Question 7:

Design a class to overload a function series() as follows: [15]

(a) void series(int x, int n) – To display the sum of the series given below:

x¹ + x² + x³ + ....... xⁿ terms

(b) void series(int p) – To display the following series: 0, 7, 26, 63 ...... p terms

(c) void series() – To display the sum of the series given below:

Ans: class Overload

{

void series (int x, int n)

{

double sum = 0.0;

for (int i = 1; i<=n; i++)

sum = sum + Math.pow(x,i);

System.out.println(sum);

}

void series (int p)

{

for (int i = 1; i<=p; i++)

System.out.print((i*i*i) – 1 + “ ”);

}

void series ()

{

double sum = 0.0;

for (int i = 2; i<=10; i++)

sum = sum + (double)1/i;

System.out.println(sum);

}

Question 8:

Write a program to input a sentence and convert it into uppercase and count and display the total number of words starting with letter 'A'.

Example:

Sample Input: ADVANCEMENT AND APPLICATION OF INFORMATION TECHNOLOGY ARE EVER CHANGING

Sample Output: Total number of words starting with letter 'A' = 4. [15]

Ans: -

class Starting_Letter_A

{

public static void main(String s)

{

int c=0,i;

char ch1,ch2;

int l=s.length();

s=s.toUpperCase();

s=" "+s;

for(i=0; i<l; i++)

{

ch1=s.charAt(i);

ch2=s.charAt(i+1);

if(ch1==' ' && ch2=='A')

c++;

}

System.out.println("Number of of wrods started with letter A: "+c);

}

Question 9:

A tech number has even number of digits. If the number is split in two equal halves, then the square of sum of these halves is equal to the number itself. Write a program to generate and print all four digits tech numbers. [15]

Example:

Consider the number 3025

Square of sum of the halves of 3025

Ans:

class TechNumber

{

public static void main()

{

int x, r, q, sq, s;

for (x = 1000; x<=9999; x++)

{

r=x%100;

q=x/100;

s=r+q;

sq=s*s;

if(x = = sq)

System.out.println(x);

}

Computer Virus

2020-07-12T20:05:00.003+05:30

A virus is a computer program that enters the computer system by attaching itself to another computer program, and spreads itself across the system. The full form of VIRUS is Vital Information Resource Under Seize.

What does a Computer virus do?

A computer virus is capable of performing the following tasks:

1) It can infect executable program files, such as word processors, spreadsheets, and the operating system program.

2) It can infect disks by attaching itself to special programs in the hard disk, called boot records. )These are the programs, the computer uses to start up.

3) It can infect a file before it is attached to an email message or transferred to a disk, and thus spread from one computer to another.

What are the in-capabilities of Computer virus?

A computer virus is incapable of performing the following tasks:

1) It cannot infect files on write protected discs (for example: CD-ROM )

2) It cannot infect computer hardware for examples: monitor and keyboard. It infects only software.

Hackers refers to the people, who use their skills to enter into computer systems without permission. Hackers are computer enthusiasts who break into secure systems to gain knowledge about them and possibly use this knowledge to play pranks.

A Cracker is malicious programmer, who gains unauthorised access to computer systems for the purpose of stealing, altering or corrupting information. Crackers often destroy confidential or crucial data of the systems they invade. They break the security of application software and create destructive programs like viruses.

Hackers

How does a Computer virus spread?

Computer viruses spread from one computer to another by transfer of infected data through emails, pen drives, or other sources.

Charts is Excel

2020-07-10T22:58:00.000+05:30

Chart in Excel is a pictorial representation of data. It allows us to present data entered into the worksheet in a visual format using a variety of graph types.

Types of Charts

How to create a chart?

1. Select the cells we want to insert into the chart, including the column titles and row labels.
2. Click the Insert tab.
3. In the Charts group, select the desired charts category.
4. Select the desired Chart type from the drop-down menu.
5. The chart will appear in the worksheet.

Different parts of an Excel chart

Chart area
Everything inside the chart window, including all parts of the chart (labels, axes, data markers, tick marks, and other elements listed here).

Plot area
The area where Excel plots our data, including the axes and all markers that represent data points.

Data series
A group of related values, such as all the values in a single row in the chart.

Axis
A line that serves as a major reference for plotting data in a chart. In two-dimensional charts there are two axes - the x-axis (horizontal / category) and the y-axis (vertical / value).

Tick mark
A small line intersecting an axis. A tick mark indicates a category, scale or chart data series.

Gridlines
Gridlines are optional lines extending from the tick marks across the plot area, thus making it easier to view the data values representing by the tick marks.

Chart text
A label or title that you add to the chart.

Legend
A legend is a key that identifies patterns, colors or symbols associate with the markers of a chart data series.

Advantages of Chart

1) It helps US to analyze and evaluate the worksheet conveniently.
2) It also holds the interest of the audience if the data is present in graphical or pictorial form, which is easier to read and understand.

Embedded chart
It is a chart object that is placed on a worksheet and saved with that worksheet when the workbook is saved.

Chart Sheet
It is a sheet in a workbook that contains only a chart. it is beneficial when we want to view a chart separately from workbook data.

Modes of Communication | Simplex, Half-Duplex and Full Duplex

2020-07-10T12:50:00.001+05:30

In a network system, when two computers transferring data (one is called sender and another one is called receiver), then this types of modes of communication is classified into following three types:

Simplex Mode

In Simplex mode communication, data can be transmitted in one direction only. In this case, any computer which is connected with the network can only send data as a sender and in opposite side the receiver computer can only receive the data. For example, Keyboard, Monitor, TV, Radio telecast, etc.

Simplex Mode

Half-Duplex Mode

In Full Duplex mode any computer in the network can send data to any other computer in the network. But not simultaneously. When one computer acts as sender then other computer acts as receiver and vice-versa. Here one channel is used for both actions i.e., sending and receiving data. For example, Conversation through Walkie-Talkies.

Half Duplex Mode

Full Duplex Mode

Full Duplex mode is also two way communication, but here data can transmit both the directions simultaneously. Which means, two computers in a network can send and receive data at the same time. Here two channels are used, one for sending and another one for receiving. For example, Telephone line, where we can talk and listen at the same time.

Full Duplex Mode

Mail Merge

2020-07-06T17:49:00.000+05:30

Mail Merge is the process of connecting main document and the data source. We can send any letter or invitation to a number of people very quickly using Mail Merge. It is very easy to proofread a single letter which is then used as the template for many others.

Advantages

1) One standard letter can be written and sent to all customers without having to manually add each name and address.
2) The letter can personalized - it looks as though the letter has been written to the individual person.
3) It's a very fast way to produce hundreds of personalized letters.

Disadvantages

1) Letters can lack the personal touch.
2) The database that provides the information for the mail merge letter must be kept up to date if ti is going to be useful.

What are the basic components of Mail Merge?

Main Document

Main document can be used for storing the information that remains same for different letters.

Data Source

The name and address that changes in every letter is inserted in the data source that contains variable fields which are later on inserted in the merged document.

Merged Document

When the main document is merged with the data source created a third document, called as the merged document that is said to be a combination of main document and the data source.

The steps followed for using Mail Merge?

1) Create the Main Document

2) Create the Data Source

3) Merge the Main Document with Data Source

Step 1: Create Main Document

1. Click on Mailings tab.

2. Under Mail Merge group click on Start Mail Merge button and select Letters option.

3. Then type your desired letter and Save it.

Creation of Main Document

Step 2: Create Data Source

1. Under Mailings tab, click on Start Mail Merge button and then select Select Recipients option.

2. Select Type New List option. Then New Address List dialog box will appear.

3. Click on Customized Columns button and then Customize Address List dialog box will appear.

4. Keep the desired field from here and delete unnecessary field (Delete --> Yes). If you want to add new field from your own, then click Add. Then click on OK button.

5. Now enter the required data in each field.

Creation of Data Source

Step 3: Merge Document

1. Keep the cursor in the desired position of the Main Document. Then click on Insert Merge Field button of Write & Insert Fields groups.
2. Click on each Field name to Insert them into the document. Then Save it to update the document.
3. Click on Finish & Merge button under Finish group and the select Edit Individual Documents. So, Merge To New Documents dialog box will appear.

4. Select on All and then Click on OK.

Mail Merge Process

Analog and Digital Communication | Communication Signal

2020-07-01T23:36:00.003+05:30

The main feature or motive in data communication system is transferring data in between two or more devices. Data can be of different types - audio, video, text, graphics, etc. In computer network, data is sent in the form of electrical signal. Electrical signal is of two types - Analog signal and Digital signal.

Analog Signal

We commonly used Analog signal in our daily life. It mainly used for voice communication (e.g., telephonic conversation). It is mainly consists in the combination of Electromagnetic Wave. Electromagnetic Waveform mainly measures with the help of the following three features -

Amplitude: Amplitude is used to measure the power or the range of the signal. As the height of the wave is high, the signal will more powerful.

Frequency: Frequency is the ability that signal creates a total number of wave form per second.

Phase: The phase involves the relationship between the position of the amplitude crests and troughs of two wave forms. Phase can be measured in distance, time or degrees.

Advantages

1) Analog signal is very useful for sending audio and video data.
2) Analog signal can be received from any part of the world.
3) Analog signal is not being effected by noise of other signals.

Analog Signal

Digital Signal

Digital signal is mainly used to communicate between computers. Digital signal is consists of two Binary Digits 0 and 1. Every digital signals is sent in the form of 0 and 1.
Digital signal can be classified with two different types - current state encoding and state transition encoding.
In current state encoding, the signal value 0 or 1 is decided on the basis of flow of voltage on every moment.
In state transition encoding, the transformation of high voltage to low voltage we assume as 1 and the transformation of low voltage to high voltage we assume as 0.

Advantages

1) Digital circuits are cheaper and easy to design as compare to Analog signal.
2) Digital circuits are more reliable.
3) Digital signal has a high level of accuracy.

Digital Signal

Differences between Analog and Digital Signal

Analog Signal	Digital Signal
1) It is suitable for sending audio and video data.	1) It is suitable for sending Text data.
2) It consists with electromagnetic wave.	It consists with binary digits 0 and 1.
3) It is costlier than Digital Signal.	3) It is cheaper than Analog signal.

Tabular Representation | MS Word

2020-06-26T17:49:00.000+05:30

A Table is a grid of cells where we arrange data in the form of row and column.

Click on the image to see in original size

How to create a table in a document?

The steps to create a table in a document are given below:

Step 1: Click on Insert tab and select Insert Table button under Table option of the Table command group.

Step 2: After appearing Insert Table dialog box, enter the number of column and row in the Number of columns box and Number of rows box respectively.

Step 3: Click on OK button.

We can also create table by dragging and selecting Column and Row from Table option of the Insert Ribbon.

Insert Row or Column in a Table

To insert a row or column -

1. Click on the desired cell and then right click on it.

2. Move the cursor on the Insert option.

3. Then, if you want to insert column then select either select Insert Column to the Left or Insert Column to the Right as your requirement, or if you want to insert row, then select either Insert Rows Above or Insert Rows Below according to your requirement.

Delete Row or Column in a Table

To insert a row or column -

1. Click on the desired row or column which one you want to delete.
2. Right click on the row or column.
3. Select either Delete columns or Delete rows as you want to delete.

Merge cell and Split cell

Using Merge cell option you can combine or join together two or more table cells located into same column or same row into a single cell.

Using Split cell option you can separate or divide a single cell into multiple cells, i.e. you can insert any number of row or column into a single cell.

Click on the image to see in original size

Table Creation in MS Word | Merge Cells and Split Cells

MS Excel Functions

2020-06-25T00:11:00.000+05:30

A function is a predefined formula that performs calculations using specific values in a particular order. Excel has many built-in functions. In another side, a formula is an expression which calculates the value of a cell. Every Excel formula starts with equal to (=) symbol.

Using of SUM function in Excel

Uses of some Excel functions

SUM()

SUM() function is used to find the sum or addition value in a particular range of cells of an Excel worksheet.

e.g.,

=SUM(A1 : A5)

Here, the addition value or summation value will return from the cell A1 to A5.

SUMIF()

SUMIF() function is used to find the sum or addition value in a particular range of cells of an Excel worksheet, but according to some criteria i.e., on the the basis of user given condition.

e.g.,

=SUMIF(A1 : A5, ">50")

Here, from the range of cells A1 to A5 will be added but only those numbers, which are more than 50.

COUNT()

COUNT() function is used to find the total number of numbers are present in a particular range of cells of an Excel Worksheet.

e.g.,

=COUNT(A1 : A5)
Here, how many total numbers are present in the range of cells A1 to A5 will return.

MAX()

MAX() function returns the maximum number from a given range of cells.

e.g.,

=MAX(A1 : A5)

Here, the maximum number will return from the range of cells A1 to A5.

MIN()

MIN() function returns the minimum number from a given range of cells.

e.g.,

=MAX(A1 : A5)

Here, the minimum number will return from the range of cells A1 to A5.

AVERAGE()

AVERAGE() function is used to find the average in a given range of cells.

e.g.,

=AVERAGE(A1 : A5)

Here, the average will return from the range of cells A1 to A5.

PRODUCT()

PRODUCT() function is used to find the multiplication value or product value in a given range of cells.

e.g.,

=PRODUCT(A1 : A5)

Here, the multiplication value will return from the range of cells A1 to A5.

Excel functions | Part - 1

TODAY()

TODAY() function is used to return system current date.
e.g.,
=TODAY()
Here, the system current date will be displayed.

NOW()

NOW() returns the system current data and time in a particular cell.

e.g.,

=NOW()

Here, the system current date and time will display in any cell, in which you will apply this formula.

IF()

As IF() function is a logical function, it returns logical values i.e., either True value or False value on the basis of user given condition.

e.g.,

=IF(A5>=50,”Good”,”Bad”)

Here, If the value of A5 is more than or equal to 50, then Good will display, otherwise Bad will display.

PMT()

PMT() is a type of financial function in MS Excel. This function calculates the payment for a loan based on constant payments and a constant interest rate.

The Calculation of PMT() function

On the above example, to find the Payable Amount we have used the following formula.

=PMT(B2/12, B3, B1)

Excel Functions | Part - 2

AutoSum (Σ)

The AutoSum command allows us to automatically return the results for range of cells for common function like SUM.

How to use AutoSum(Σ)
1. Select the cell that the sum will appear in that is outside the cluster of cells whose values will be added.
2. Click the AutoSum button (Greek letter sigma Σ) on the Formula tab.

3. Highlight the group of cells that will be summed.
4. Press the ENTER key on the keyboard or click the tick (✔) mark button on the Formula bar.

Creating, Editing and Saving a document

2020-06-22T21:58:00.001+05:30

How to save a document?

To save a document, follow the steps:
Step 1: Click on Save or Save or Save As option from file or press Ctrl + S. Then Save As dialog box will appear.
Step 2: Choose the location from the left side of the box, where we want to save.
Step 3: Give the desired file name in the File name: text box.
Step 4: Click one Save button.

Save As dialog box

Differences between Save and Save As

Save helps us to lastly preserved file with the latest content, while Save As helps to store a new file or to store an existing file to a new location with the same name or a different name.
The short-cut key of Save is Ctrl + S, while the short-cut key of Save As is F12.

Differences between Cut and Copy

The Cut command removes the selected data from its original position, while Copy command creates a duplicate of the original.
The short-cut key of Cut is Ctrl+X and the short-cut key of Copy is Ctrl+C.

Page Orientation

There are two following two types of page orientation supports in MS Word:

Portrait: It is the vertical align of any page. It is taller and less wider than Landscape.
Landscape: It is horizontal align of any page. It is more wider and lesser in height than Portrait.

Alt + F4 vs Ctrl + F4

By pressing Alt + F4, the current Word Document will be closed, but Word window will remain open. But, by pressing Ctrl + F4, the Word window will be closed.

MS Word | Introduction

2020-06-22T19:46:00.003+05:30

MS Word is an application, word-processing software designed and developed by Microsoft Corporation in USA. The extension name of MS Word file is .DOCX (from 2007 onward).

Introduction to MS Word window and it's elements

MS Word window with it's elements

Title Bar

It is the top most bar of the MS Word window. It show the name of the current file name. By default it opens with Document1. At the right side of the bar Minimize, Maximize / Restore and Close buttons are placed.

Ribbons

There are total 7 Ribbons present in MS Word window - Home, Insert, Page Layout, References, Mailings, Review, View. Each and every Ribbon has some predefined command groups, such as Home has - Clipboard, Paragraph, Font, Style, Editing.

Status Bar

Status Bar is the bottom most bar of the MS Word window. It displays the current position of the cursor and many more statistics about the current document, such as total number of words, paragraphs, etc. present in the current document.

Horizontal and Vertical Scroll Bar

If the document size becomes very big, then it will not fit on the monitor screen. Then we scroll up and down (using Vertical Scroll Bar) or right and left (using Horizontal Scroll Bar) to see the invisible part of the document.

Ruler

Ruler is used to set the margin of the current document page from all the sides (4 sides).

Text Area

Text Area is the main working area of Word window, where we type anything or insert any image. It presents just below of Ruler.

Quick Access Tool Bar

Quick Access Tool Bar contains some frequently used options with it's icons, such as Save, Open, Copy, Paste, etc.

2020-06-19T23:58:00.001+05:30

Types of Operator in Java Part - 1

Microsoft Excel | Introduction

2020-06-19T18:08:00.000+05:30

Microsoft Excel is a spreadsheet based application software of MS Office suit productivity software, developed and published by Microsoft Corporation in USA. The extension name of Excel file (for Office version 2007 onward) is .XLSX.

Introduction to Excel window and it's elements

MS Excel window with it's elements

Workbook:

A workbook is an Excel file that contains one or more worksheets to help you organize data. You can create a new workbook from blank workbook or a template.

Worksheet:

Each and every page of a workbook is known as worksheet. By default, there are three worksheets present in a Workbook - Sheet1, Sheet2, Sheet3. We can increase the number of worksheets as requirement.

Title Bar:

Title Bar is the top most bar in Excel window. It displays the name of the current workbook and at the right side of the bar, Minimize, Maximize / Restore and Close buttons are placed.

Ribbon:

There are total 7 Ribbons present - Home, Insert, Page Layout, Formulas, Data, Review, View. Each and every Ribbon has some predefined command groups , such as Home has Clipboard, Font, Alignment,Number, Styles, Cells, Editing total 7 command groups.

Row and Column:

Row lays in horizontally, while column lays in vertically. In Excel 2010, Row numbers ranges from 1 to 1048576 and Column number ranges from A to XFD, in total 16384 columns.

Cell:

The intersection of row and column is known as Cell. Each cell has Cell Address, like A1, A2, B4, etc. The first cell address is A1 and last cell address is XFD1048576.

Active cell:

An active cell refers to the currently selected cell in a spreadsheet. It can be identified by a bold outline that surrounds the cell.

Status Bar:

Status Bar is the bottom most bar in Excel. It shows the current status of the worksheet. It also notifies us about Caps Lock, Num Lock, Scroll Lock, etc. ON or OFF state.

Name box:

Name box shows the address of Active cell. On which cell the mouse pointer will be clicked, the Name box will display that particular cell address.

Formula Bar:

The Formula Bar is where data or formulas we enter into a worksheet appear for the active cell. The Formula Bar can also be used to edit data or formula in the active cell.

Horizontal and Vertical Scroll Bar:

Normally, the size of the worksheet is very big, which does not fit in monitor. So, to move on to invisible part of the worksheet, we use Scroll Bar. To move up and down, we use Vertical Scroll Bar, while to move right and left, we use Horizontal Scroll Bar.

Different types of Cell References

Relative reference:

By default, all cell references are relative references. When copied across multiple cells, they change based on the relative position of rows and columns. For example, if you copy the formula =A1+B1 from row 1 to row 2, the formula will become =A2+B2. Relative references are especially convenient whenever you need to repeat the same calculation across multiple rows or columns.

Absolute reference:

An absolute reference in Excel refers to a reference that is "locked" so that rows and columns won't change when copied. To create an absolute reference, add a dollar sign ($) before the row and column. For example, if we write formula, =$A$1 * 10, that means A1 cell is locked and after copying in the next cell, the cell reference will not change.

Mixed reference:

Mixed reference is the combination of Relative reference or Absolute reference. That means here, either row or column can be locked with $ sign as Absolute reference and other one will be unlocked as Relative reference. For example, =$A1 * 10, which means A column is locked but not row. So, after copying in the next cell, the formula will be =$A2 * 10, that means column remain same and row just changed.

Array (Single Dimensional and Double Dimensional)

2020-06-13T20:24:00.000+05:30

An array is a structure created in the memory to represent a number of values of the same data type with variable having the same variable name along with different subscript (location). An array is also called Subscripted Variable. An array with empty [ ] represents an unfixed number of cells in the memory.

An array is basically of two types:

1) Single Dimensional Array

2) Double Dimensional Array

Creating Single Dimensional Array (SDA)

The syntax to crate a single dimensional array is as shown below:

<Data type> <variable>[ ] = new <Data type>[size of the array];

e.g., int m[ ] = new int[10]; means m is an integer type array that can store 10 data items in the memory with different subscripts along X-axis. However, the storage of the array elements begin with the 0th subscript as shown below:

Here, m0 can be written as m[0] where m is subscripted variable and 0 is subscript.

In this illustration shown above, 0, 1, 2, ......, 9 are referred to as subscripts and they help in both input and output of the array elements.

Mathematical Library Methods

2020-06-11T12:13:00.002+05:30

The library methods (functions) are the in-built methods designed by the developers. These predefined functions help the user to perform certain tasks easily and quickly which are frequently used in Java programming. All the Mathematical functions are included in a class called Math under java.lang package.

Math.min()

It returns the minimum of two numbers. It returns int/long/double type value depending upon the type of arguments passed to it.
Syntax: <Return data type> <variable> = <Function name(argument 1, argument 2)>;
e.g., double m = Math.min(-4.5, -5.4);
Output: -5.4

Math.max()

It returns the greatest value of two numbers. It returns int/long/double type value depending upon the type of arguments passed to it.
Syntax: <Return data type> <variable> = <Function name(argument 1, argument 2)>;
e.g., double m = Math.max(9.2, 9.45);
Output: 9.45

Math.pow()

This method is used to find the power raised to a given base value. It always returns a double type value.
Syntax: <Return data type> <variable> = <Function name(argument 1, argument 2)>;
e.g., double m = Math.pow(2,4);
Output: 16.0

Math.sqrt()

It is used to find the square root of a positive number. It returns a double type value.
Syntax: <Return data type> <variable> = <Function name(Positive number)>;
e.g., double m = Math.sqrt(7.29);
Output: 2.7
Square root of a negative number is an imaginary number.

Math.cbrt()

It is used to find the cube root of a positive number or negative number. It returns a double type value.
Syntax: <Return data type> <variable> = <Function name(number)>;
e.g., double m = Math.cbrt(27.791);
Output: 3.1

Math.log()

This function is used to find the natural logarithmic value of a given argument. It always return a double type value.
Syntax: <Return data type> <variable> = <Function name(number)>;
e.g., double m = Math.log(6.25);
Output: 1.8325

Math.abs()

It always returns the absolute value of an argument (magnitude of the number without its sign, i.e., a positive value). The return value may be int/long/double data type depending upon the input arguments.
Syntax: <Return data type> <variable> = <Function name(number)>;
e.g., double m = Math.abs(-6.25);
Output: 6.25

Math.round()

This function return the value of a number rounded to its nearest integer. If the fractional part is less than 0.5 then it returns the same integer value, otherwise it returns the next higher integer. It returns the value in long or int type.
Syntax: <Return data type> <variable> = <Function name(argument)>;
e.g., double m = Math.round(8.5);
Output: 9
e.g., double m = Math.round(-8.5);
Output: -8

Math.rint()

This function returns the nearest integer of a given fractional number. The return data type will always be double.
Syntax: <Return data type> <variable> = <Function name(argument)>;
e.g., double m = Math.round(8.5);
Output: 8.0
e.g., double m = Math.round(-9.5);
Output: -10.0

Math.ceil()

It returns the next higher integer number that is greater than or equal to the argument. It always return the value as a double data type.
Syntax: <Return data type> <variable> = <Function name(argument)>;
e.g., double m = Math.ceil(8.5);
Output: 9.0
e.g., double m = Math.round(-8.5);
Output: -8.0

Math.floor()

It returns the lower integer number that is less than or equal to the argument. It always returns the value as a double data type.
Syntax: <Return data type> <variable> = <Function name(argument)>;
e.g., double m = Math.floor(8.912);
Output: 8.0
e.g., double m = Math.round(-8.912);
Output: -9.0

Math.floor()

It results in the exponential value of an argument x (i.e.e^^x). It returns a double type value.
Syntax: <Return data type> <variable> = <Function name(number)>;
e.g., double m = Math.exp(6.25);
Output: 518.0128

Iterative Constructs with Nested Loop

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A construct in which a block of statements gets executed repeatedly unless the required task has been completed. Such repetitive construct is known as an iterative construct or a Loop.

Iterative means repeated execution of a set of statements. This can be achieved by using a loop.

Based on the flow of control, the looping constructs can be categorized into two types. They are:

Entry Controlled Loop
Exit Controlled Loop

Entry Controlled Loop

A looping construct in which the condition is checked in the beginning. If the condition is true, the control is allowed to enter into the loop otherwise the entry will be denied. There are two types of looping construct under this category:

for Loop

The for loop is used when number of iterations is fixed and known. It is a fixed or known iterative

looping construct.

Components of for loop structure are:

control variable with initial value
test condition
iteration (increment / decrement step value)

syntax:

for(initialization; test condition; iteration)

{

// loop body

}

e.g.,

for(a=1; a<=10; a++)

{

System.out.prinlnt(a);

s=s+a;

}

while Loop

Sometimes, it may happen that a set of statements are to be executed repeatedly without knowing the number of iterations, while loop is used to solve the purpose. In this looping construct, a block of statements gets executed repeatedly unless the given condition is false. while loop is unfixed or unknown iterative loop.

syntax:

initialization;

while(test condition)

{

//statements

iteration;

}

e.g.,

int p=1000, r=10;

while(p<=10000)

{

si = (p * r) / 1000.0;

p = p + si;

}

Exit Controlled Loop

This is another type of looping construct in which condition is checked at the exit point (end point) of the loop. The control will repeat for the next iteration or exit from the loop depending on the condition is true or false receptively. Here, the body of the loop will execute at least once.

do-while Loop

The do-while loop also works in the same way as while loop. It is also unfixed or unknown iterative loop. Only difference is the position at which the condition will be checked. In do-while loop the condition is checked at the end of the loop.
syntax
initialization;
do
{
//statement
iteration;
}while(test condition);

e.g.,

int p=1000, r=10;

{

si = (p * r) / 1000.0;

p = p + si;

}while(p<=10000);

Use of 'break' statement in loop

Sometimes, it may happen that the loop has not been completed but the requirement has been fulfilled. The user then would like to terminate the loop without its completion. In this situation, break statement is used to solve the purpose. Hence, the break statement is used in a loop to send the control out of the loop, if certain condition is true.
eg.,
for(i=1; i<=10; i++)
{
if(i == 5)
break;
s = s + i;
}

In the above example, the loop will add the numbers from 1 to 4. As soon as the value of 'i' becomes 5, the break statement will be executed. As a result control will exit from the loop.

Use of 'continue' statement in loop

The continue statement is opposite of the break statement. When continue statement is invoked, the control goes back to check the condition of the loop by ignoring rest statements of the loop.

eg.,
for(i=1; i<=10; i++)
{
if(i == 5)
continue;
s = s + i;
}

In the above example, the loop will run from 1 to 10 times, but as soon as, the value of 'i' becomes 5, the continue statement will be executed. As a result, the control will be forced to move back for the next iteration by ignoring the last statement of the loops.

Infinite loop

A loop that repeats for infinite number of iterations is known as infinite loop. It is also called endless loop. Here, the test condition always return true value.
eg.,
for(;;)
//statements

Nested loop

When you use a loop within another loop is said to be a nested loop. In the nested loop, you will notice that the inner loop repeats a number of times for each repetition of the outer loop.
e.g.,
int i, j;
for(i=1; i<=5; i++) // outer loop
{
for(j=1; j<=i; j++) // inner loop
{
System.out.print(j);
}
System.out.println();
}

OUTPUT
1
12
123
1234
12345

Conditional Statements

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if statement

This statement checks the condition first. If the condition is true then the next statement is executed

otherwise it is ignored.

e.g.,

if(a>10)

c = a * a;

System.out.println(c);

In the example shown above, if the given condition (i.e., a is greater than 10) is true then it will calculate the square of the number 'a' otherwise, it will ignore this statement and will go to the next statement. In that case, it will print the default value of c as 0.

if-else statement

If you want to execute either of the two statements depending upon a given condition then 'if-else' statement is used.

e.g.,

if(a > b)

max = a;

else

max = b;

The example shown above illustrates that max is assigned either with the value 'a' or 'b' depending upon the condition (a>b) us true or false.

if-else-if statement

Sometimes, it may happen that the given condition is false and the user wants to check another condition for taking necessary action, under this situation 'if-else-if ' statement is used.
e.g.,
if(marks >= 75)
System.out.println("Distinction");
else if(marks >= 60)
System.out.println("First Division");
else if(marks >= 50)
System.out.println("Second Division");
else
System.out.println("Third Division");

if-else and nested if-else | Part 1

Nested if statement

When 'if' statement is used within another 'if' statement, the construct is said to be a 'Nested if ' statement. In this construct, if the given condition is true then it further checks another if condition and carries out the instructions accordingly.
e.g.,
if( a>= 10)
{
if(a < 100)
c = a * a;
}
else
c = a * a * a;

switch-case statement

In a switch case statement, a number of blocks are created under different cases. All the cases are enclosed within curly braces { } under switch statement. A particular case is executed based on the given value (user's choice) of control variable passed as an argument to the switch () statement.
e.g.,
switch (a)
{
case 1:
System.out.println("Good");
break;
case 2:
System.out.println("Better");
break;
System.out.println("Best");
break;
default:
System.out.println("Invalid");
}
A particular case will be executed when matched with the value of control variable 'a'. The default case will be executed only when the value of 'a' doesn't match with any of the cases listed above.

Terms related to switch statement

Control Variable

The variable passed as an argument to the switch statement that decides which case is to be executed is known as a control variable.

break statement

This is the statement used at the end of each case which acts as the case terminator. As soon as break is encountered, the control is forced to move out of the switch block.

default statement

If no case is matched in the switch block for a given value of control variable, default case is executed implicitly.

Fall Through

In case a break statement is not used at the end of a case, the control enters into the next case for execution. This condition is said to be Fall Through.

Introduction to Java

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Java is a an object oriented, high level programming language developed by James Gosling along with his associates at Sun Micro System (a software company), in USA. Initially it was named OAK (a tree outside Gosling's office). The name OAK remained only for some hours until the development team realised that another language is also available with this name. Finally,on the coffee table they decided a professional name for the language as Java. It was primarily developed to help users in web designing but later on it emerged as a full-fledged programming language in 1991.

Java gained wide popularity amongst the users due to its platform independence. The platform independence means the program in Java language can be executed on any types of Operating System (OS).
Java language allows writing a program in two ways. They are:

Java application or Standalone system: It is a Java program that is developed to run on a computer without any help of a web browser. It is also known as standalone system.
Java applet or Internet applet: It is a program written in Java language that can be included in a web page in the same way as a picture or a clip is included. Java applets are run with the help a Java supported web browser.

Features of Java Language

Java is object oriented programming language.
It is a high level programming language.
It is platform independent.
It uses compiler as well as interpreter.
It is a robust language.
It is case sensitive.

Java Compiler and Interpreter

Java compiler is a system software that converts a program in Java (Java source code) into an intermediate binary form called Byte Code. Further, the byte code is converted into machine code suitable to a specific platform known as Java Interpreter.

Java Interpreter enables a computer to execute a Java program as well as a program written in other language compiled into Java byte code. This is the reason, Java interpreter is said to be Java Virtual Machine (JVM).

It is important to know that Java machine code varies for different platforms such as windows (single user OS), UNIX (multi-user OS) including other operating systems.

Values and Data Types

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ASCII Codes

ASCII stands for American Standard Code for Information Interchange. It uses 7 bits code for representing each character. It includes 256 characters but only 128 characters are used while designing and executing a program. ASCII code represents these characters as numbers, with each letter assigned a number from 0 to 127. The ASCII codes of some of the characters used in Java programming are shown below:

Characters	ASCII Codes
Blank space (white space)	32
0 to 9 (Numbers)	48 – 57
A to Z (Capital Alphabets)	65 – 90
a to z (Small Alphabets)	97 – 122

Tokens

Token is defined as each individual item or component of Java program that carries some meaning and takes active part in program execution.

Keywords

Keywords are the reserved words which are preserved by the system and carry special meaning for the system compiler. They have already been defined in the language and we cannot use them as names for variables or identifiers, e.g., class, public, throws, for, sqrt, etc.

Identifiers

Identifiers is a term used for naming a block of statements by which they are identified in a Java program. Identifiers can be a class name, a function name, an object , a variable name or an interface name. Following are some naming rules for identifiers:

Identifier’s name cannot be same with Keywords or Reserved words.
Identifier’s name always starts with alphabets, not with numbers.
No special characters are used within an identifiers name except underscore (_) or dollar ($).
Blank space (white space) is not allowed in between identifiers name.

Literals

The term constants are referred to as literals in Java programs that remain unchanged during entire execution of the program.

The various types of literals used in Java are as follows:

Integer Literals: The whole numbers (positive or negative) are known as integer literals. Decimal point is not allowed in Integer Literals. e.g., 16, 357, 7856, 66845, etc.

Real Literals: Real literals are also called as floating point numbers. They are the fractional numbers. The placement of decimal point may not be same in real numbers. e.g., 3.45, 85.6, 557.65, etc.

Character Literals: A single letter or a digit or any special symbol enclosed within single quotes is known as a character literal. It does not take part in arithmetical calculations. e.g., ‘B’, ‘u’ ‘6’, ‘?’, etc.

String Literals: A group of characters enclosed within double quotes is known as a String literal. e.g., “PROCESS”, “System”, “Salary – 2018”, “4357”, etc.

Boolean Literals: Boolean literals are true and false. A Boolean literal can either be true or false at a time.

Null Literal: Null literal denotes the absence of a value. It is used to initialize an object or array.

e.g., int n = null;

String s = null;

Operators
Operators are the symbols or signs used to specify the operations to be performed in a Java expression or statement.
To know different types of operators and their functions, click here.

Punctuators or Separators
Punctuators or Separators are some punctuation signs or some special characters in Java, which are used to separate the variables or the characters. e.g., comma (,), semicolon (;), dot (.), parenthesis (), brackets {}, etc.

Data Types

Date type basically refers to as the types of data,a memory location can hold. Java supports mainly following two types of data:

Primitive Data Type (Built-in)
Non-primitive Data Type (User-defined)

Primitive Data Types

Primitive Data Types are the basic or fundamental data types used to declare a variable. There are following 8 primitive data types present in Java:

Types		Size (Bytes)	Default
Integer	byte	1	0
	short	2	0
	int	4	0
	long	8	0
Real	float	4	0.0
Real	double	8	0.0
Character	char	2	\u0000
Boolean	boolean	1 bit	false

Non-primitive Data Types

A non-primitive data type is one that is derived from primitive data types. We also may say that a number of primitive data types are used together to represent a non-primitive data type. Hence, a non-primitive data type is also called a composite data type.

Type conversion

If various types of data are used in an expression, a question obviously comes to your mind that what type of result it will return after execution. In fact, the system converts the result into a specific data type known as Type Conversion. Basically, the data type conversion take place in two ways as discussed below:

Implicit type conversion

In a mixed mode expression, when the smaller data types are converted into higher data type automatically, then it is known as Implicit type conversion. It is also known as Coercion.

e.g., int a;

long b;

long c = a + b;

Explicit type conversion

In a mixed mode expression, when the smaller data types are need to be converted into smaller data type, which is normally not possible, then we convert them forcefully using type cast operator (). This is known as Explicit type conversion. It is also known as Type casting.

String Handling

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Strings, which are widely used in Java programming, are a sequence of characters. Basically, String is a class in Java and we work with objects of String class.

Java String literal is created by using double quotes. For Example:

String s = “Learn Java”

Some String methods with their descriptions

int length()

This function returns string length (i.e., total number of characters present in a String)

char charAt(int index)

This function returns a character value for the particular position.

String Handling in | Java Part - 1

int indexOf(char ch)

This function returns the index position of the particular character in the String.

int lastIndexOf(char ch)

This function returns the index position of the last occurrence of a character in a String.

String substring(int start_index)

This function is used to extract a set of characters simultaneously from a given index up to end of the string.

String substring(int start_index, int last_index)

It is another modification of substring function. It will return a set of characters simultaneously from start index up to the last index of the string (excluding the character present at the last index).

String toLowerCase()

This function converts all the characters (if in upper case) of a given string into lower case. If any character is already in lower case or is a special character then it will remain same.

String toUpperCase()

This function converts all the characters (if in lower case) of a given string into upper case. If any character is already in upper case or is a special character then it will remain same.

boolean isLowerCase()

This function is used to check whether all the characters of a given string are in lower case or not. It returns boolean value true if all the characters are in lower case, otherwise false.

String Handling in | Java Part - 2

boolean isUpperCase()

This function is used to check whether all the characters of a given string are in upper case or not. It returns boolean value true if all the characters are in upper case, otherwise false.

String concat(String s)

This function is used to concatenate (join) two strings together and returns in one string.

String replace(char old_char, char new_char)

This function is used to replace a character by another character in the given string and returns a new string.

String replace(old_sequence_of_characters, new_sequence_of_characters)

This function is also used to replace a sequence of characters by another sequence of characters at all its occurrences in the string.

boolean equals(String s)

This function is used to compare two strings together to check whether they are identical or not. It returns a boolean type value true if both are same, otherwise false.

boolean equalsIgnoreCase(String s)

This function is also used to compare two strings to check whether both are identical or not after ignoring the case (i.e., corresponding upper and lower case characters are treated to be the same). It also returns a boolean type value as true or false.

int compareTo(String s)
This function is also used to compare two strings. But, it not only checks the equality of two strings but also checks whether a string is bigger or smaller than the other. It will return 0 if both the strings are same, a negative value if first string is smaller and a positive value if the first string is bigger.

String Handling in Java | Part - 3

How to take String as input?

We can take String as input through either main () method or using Scanner class. The procedure of taking input are given below:

Using main() method

Step 1: write the codes like below:

Step 2: At the time of taking input use double quotes (" ").

Using Scanner class

Step 1: Import the java class java.util where the Scanner class is located.

import java.util.*;

Step 2: Create object of Scanner class.

Scanner sc = new Scanner(System.in);

Here, sc object is created of Scanner class.

Step 3: Use either next() method or nextLine() method with object of Scanner class, as your requirement. next() method is for single word and nextLine() is for multiple words.

String s1 = sc.next();

String s2 = sc.nextLine();

Here, s1 will accept only one word and s2 will accept multiple words.

Introduction to Object Oriented Programming (OOP)

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Class

A class is a user defined blueprint or prototype from which objects are created. It represents the set of properties or methods that are common to all objects of one type.

Object

It is a basic unit of Object Oriented Programming and represents the real life entities. A typical Java program creates many objects, which as you know, interact by invoking methods. An object consists of :

State : It is represented by attributes of an object. It also reflects the properties of an object.
Behavior : It is represented by methods of an object. It also reflects the response of an object with other objects.

Let us consider an example of real world class to understand the way different characteristics and common behaviours are embedded in its objects.

The syntax to create an object in Java:

ClassName ObjectName = new ClassName();

How to create objects of the above mentioned class?

Object 1:

TelevisionSet objSony = new TelevisionSet();

Object 2:

TelevisionSet objLG = new TelevisionSet();

Let us take an example to understand as how software class and objects will be used for programming purpose.

In the structure shown above, the class ‘Rectangle’ is designed with the data members (i.e. states or attributes) – ‘length and breadth’ and member functions –‘input(), calculate() and display()’. The objects can be created as shown below:

Object 1

Rectangle Area = new Rectangle();

Object 2

Rectangle Perimeter = new Rectangle();

The structure shown above, states when the objects Area and Perimeter are created then each object will automatically possess the data members and member function described within the class Rectangle. The allocation of data members pertaining to each object can be different but the function to be carried on them will be common.

Hence,

Area.input() : will accept length and breadth of object Area

Area.calculate () : will perform calculations by using length and breadth of object Area.

Area.display() : will display the result of calculation of object Area.

Similarly, we can show the above tasks for the object Perimeter.

Principles of Object Oriented Programming (OOP)

1) Data Abstraction

The ‘Data Abstraction’ is defined as an act of representing the essential features without knowing background details.

2) Encapsulation

Wrapping of data and functions of an object as a unit that can be used together in a specific operation is known as ‘Encapsulation’.

3) Inheritance

Inheritance is the process in which objects of one class can link and share some common properties from the objects of another class.

4) Polymorphism

Polymorphism is the process of using a function for more than one purpose. It allows the use of different internal structures of the objects by keeping the same external interface.

The advantages of OOP

· Data values are secured.

· Mishandling of data is protected.

· Error detection and correction become easier.

· Easier in coding complex programs.

Some examples of OOP

Java, C++, Small Talk, Eiffel, Python are some of the Object Oriented Programming Languages.