小志的作業區

產業實習心得報告簡報

2009-12-31T14:41:00.000+08:00

Lab Recursive method

2009-06-15T21:18:00.000+08:00

Write a recursive method to compute Fibonacci series.

Hint:

1.
fib(n)=fib(n-1)+fib(n-2)

2.
public static long fib(int n)

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class LabRecursive {

public static double fib(int n)

{

if((n==1) || (n==2))

return 1;

else

return fib(n-1)+fib(n-2);

}

public static void main (String args[])

{

int n;

n = 8;

System.out.println("F(" + n + ") = " + (int)fib(n));

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

System.out.print((int)fib(a) + " ");

}

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附註：

Lab Factorial

2009-06-15T21:04:00.000+08:00

Write a Java program that computes N! where N is a positive integer.

Hint:

public static long factorial(int n)

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class LabFactorial {

public static double factorial(int n) {

if(n==1)

return 1;

else

return n * factorial(n-1);

}

public static void main (String args[]) {

int n;

n = 10;

System.out.println((int)factorial(5));

System.out.println((int)factorial(10));

System.out.println((int)factorial(15));

}

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附註：

Lab Hanoi Tower

2009-06-15T20:50:00.001+08:00

The pseudocode for Hanoi Tower is as follows:

solve(N, Src, Aux, Dst)
if N is 0 return
solve(N-1, Src, Dst, Aux)
Move N from Src to Dst
solve(N-1, Aux, Src, Dst)

Write the Java program based on the pseudocode in the above.

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class LabHanoiTower {

public static void move(int n, int s, int e)

{

System.out.println("move "+ n + " : " + s + " -> " + e);

}

public static void exchange(int n, int s, int m, int e)

{

Hanoi(n-1, s, e, m);

move(n, s, e);

Hanoi(n-1, m, s, e);

}

public static void Hanoi(int n, int s, int m, int e)

{

if(n==1)

move(n, s, e);

else

exchange(n, s, m, e);

}

public static void main (String args[]) {

int n;

n = 4;

Hanoi(n, 1, 2, 3);

}

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附註：

Lab Modular Sorting

2009-06-01T21:15:00.001+08:00

Write a sort method which takes a double array as parameter
and returns the sorted array. Call this method in a main program.
Hint: The lab is a rewriting of Lab Sorting
to make the sorting procedure a reusable method.

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class LabModularSorting {

public static void sort (double score[])

{

int i, j;

double temp;

for(i=0; i<score.length; i++ )

for(j=0; j<score.length-1; j++)

if(score[j] < score[j+1])

{

temp = score[j];

score[j] = score[j+1];

score[j+1] = temp;

}//if

}//sort

public static void main (String args[]) {

Scanner keyboard = new Scanner(System.in);

int i;

double[] score = new double[5];

System.out.println("Enter 5 scores:");

for(i = 0; i < score.length; i++)

score[i] = keyboard.nextDouble();

sort(score);

for(i = 0; i < score.length; i++)

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

}//main

}

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附註：

Lab Array

2009-06-01T20:55:00.001+08:00

Study Display 6.1, and then write a program that can sort numbers in ascending order.

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class LabArray {

public static void main (String args[]) {

Scanner keyboard = new Scanner(System.in);

double[] score = new double[5];

//double[] score2 = new double[5];

int i, j;

double temp;

System.out.println("Enter 5 scores:");

for(i = 0; i < score.length; i++)

score[i] = keyboard.nextDouble();

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

for(j=0; j<score.length-1; j++) {

if(score[j] < score[j+1]) {

temp = score[j];

score[j] = score[j+1];

score[j+1] = temp;

}//if

}//for j

}//for i

for(i = 0; i < score.length; i++)

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

}//main

}

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附註：

Lab: Static Method II

2009-05-25T21:16:00.001+08:00

Define a Complex class with a static method for computing complex addition. Use (2+3i)*(4+5i) in your test.

class程式碼

------------------------------------------------<程式碼開始>--------------------------------------

public class ADTClass {

private int realNum = 0, imaginaryNum = 0;

public ADTClass(int realNum, int imaginaryNum) {

this.realNum = realNum;

this.imaginaryNum = imaginaryNum;

}

public ADTClass multiplication(ADTClass f) {

ADTClass ans = new ADTClass(1, 1);

ans.realNum = this.realNum * f.realNum - this.imaginaryNum * f.imaginaryNum;

ans.imaginaryNum = this.imaginaryNum * f.realNum + f.imaginaryNum * this.realNum;

return ans;

}

public String toString() {

return realNum + "+" + imaginaryNum + "i";

}

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主程式碼

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class StaticMethodII {

public static void main (String args[]) {

ADTClass f1, f2;

f1 = new ADTClass(2, 3);

f2 = new ADTClass(4, 5);

System.out.println("f1 = " + f1.toString());

System.out.println("f2 = " + f2.toString());

System.out.println("f1 x f2 = " + f1.multiplication(f2).toString());

}

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附註：

Lab Magic Parking Tower

2009-05-25T21:03:00.001+08:00

A parking tower is out of order someday. If you park a Benz, you will end up with a Torben. Write a program to simulate this scenario. First create a class called CarParked which has a static method called outOfOrder. Name an object called yourCar, which happens to be a Benz. Your program should contain a class called CarParked and a test program called CarParkedDemo which test the method by CarParked.outOfOrder(yourCar).

Hint: You may study Display 5.14 to get some ideas.

class程式碼

------------------------------------------------<程式碼開始>--------------------------------------
public class CarParked {

private String name;

public CarParked(String YourCar) {

this.name = YourCar;

}

void setCar (String YourCar) {

this.name = YourCar;

}

static CarParked outOfOrder(CarParked name) {

name.setCar("Torben");

return name;

}

public String toString() {

return name;

}

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主程式碼

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class CarParkedDemo {

public static void main (String args[]) {

CarParked Car = new CarParked("Benz");

System.out.println("parking " + Car);

CarParked.outOfOrder(Car);

System.out.println("out " + Car );

}

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附註：

Lab Static Method

2009-05-11T20:29:00.001+08:00

Define a Complex class with a static method for computing complex addition. Use (2+3i)+(4+5i) in your test.

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

class ADTClass {

private int realNum = 0, imaginaryNum = 0;

public ADTClass(int realNum, int imaginaryNum) {

this.realNum = realNum;

this.imaginaryNum = imaginaryNum;

}

public static ADTClass add(ADTClass a, ADTClass b) {

ADTClass ans = new ADTClass(1, 1);

ans.realNum = a.realNum + b.realNum;

ans.imaginaryNum = a.imaginaryNum + b.imaginaryNum;

return ans;

}

public String toString() {

return realNum + "+" + imaginaryNum + "i";

}

public class LabStaticMethod {

public static void main (String args[]) {

ADTClass f1, f2;

f1 = new ADTClass(2, 3);

f2 = new ADTClass(4, 5);

System.out.println("f1 = " + f1.toString());

System.out.println("f2 = " + f2.toString());

System.out.println("f1 + f2 = " + ADTClass.add(f1, f2).toString());

}

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附註：

Lab Math methods

2009-05-11T20:14:00.000+08:00

Compute the following mathematical functions.

Math.round(3.2)
Math.round(3.6)
Math.floor(3.2)
Math.floor(3.6)
Math.ceil(3.2)
Math.ceil(3.6)

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

import java.math.*;

public class LabMath {

public static void main (String args[]) {

System.out.println("Math.round(3.2) = " + Math.round(3.2) );

System.out.println("Math.round(3.6) = " + Math.round(3.6) );

System.out.println("Math.floor(3.2) = " + Math.floor(3.2) );

System.out.println("Math.floor(3.6) = " + Math.floor(3.6) );

System.out.println("Math.ceil(3.2) = " + Math.ceil(3.2) );

System.out.println("Math.ceil(3.6) = " + Math.ceil(3.6) );

}

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附註：

Lab Finding the max of three numbers

2009-05-11T20:05:00.000+08:00

Write a static method that computes the maximum of three float numbers.

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

import java.util.Scanner;

public class LabFindingmax {

public static float maximun(float n1, float n2, float n3) {

if(n1 > n2 && n1 > n3)

return n1;

else if(n2 > n1 && n2 > n3)

return n2;

else

return n3;

}

public static void main (String args[]) {

Scanner Keyboard = new Scanner(System.in);

float a, b, c;

System.out.println("Finding the max of three numbers\nNumber 1:");

a = Keyboard.nextFloat();

System.out.println("Number 2:");

b = Keyboard.nextFloat();

System.out.println("Number 3:");

c = Keyboard.nextFloat();

System.out.println("Max = " + maximun(a, b, c) );

}

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附註：手動輸入三個float數，找出最大值。

Lab Java Constructor

2009-05-04T20:37:00.000+08:00

Write constructors in the lab Fraction Addition.

class程式碼

------------------------------------------------<程式碼開始>--------------------------------------
public class Fractions {

private int numerator, denominator, red;

public Fractions(int numerator, int denominator) {

this.numerator = numerator;

this.denominator = denominator;

}

public Fractions add(Fractions f) {

int x, a, b;

Fractions ans = new Fractions(1, 1);

ans.numerator = f.denominator * this.numerator + f.numerator * this.denominator;

ans.denominator = f.denominator * this.denominator;

red = reduction (ans.numerator, ans.denominator);

ans.numerator = ans.numerator / red;

ans.denominator = ans.denominator / red;

return ans;

}

public Fractions multiply(Fractions f) {

Fractions ans = new Fractions(1, 1);

ans.numerator = f.numerator * this.numerator;

ans.denominator = f.denominator * this.denominator;

red = reduction (ans.numerator, ans.denominator);

ans.numerator = ans.numerator / red;

ans.denominator = ans.denominator / red;

return ans;

}

private int reduction(int a, int b) {

int x;

if(a<b) {

x = a;

a = b;

b = x;

}

while (b != 0) {

x = a % b;

a = b;

b = x;

}

return a;

}

public String toString()

{

return (numerator + "/" + denominator);

}

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主程式碼

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class JavaConstructor {

public static void main (String args[]) {

Fractions f1 = new Fractions(4, 2), f2 = new Fractions(1, 3);

System.out.println("f1 = " + f1.toString());

System.out.println("f2 = " + f2.toString());

System.out.println("f1 + f2 = " + f1.add(f2).toString());

System.out.println("f1 * f2 = " + f1.multiply(f2).toString() + "\n");

}

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附註：

Lab Method Overloading

2009-05-04T20:15:00.000+08:00

依據Class definition 3，修改程式使其接受三種setDate

date1.setDate(1,2,2008);
date2.setDate("February",2, 2008);
date3.setDate(2008);

class程式碼

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class MethodOverloading {

public static void main (String args[]) {

DateFourthTry date1 = new DateFourthTry();

DateFourthTry date2 = new DateFourthTry();

DateFourthTry date3 = new DateFourthTry();

date1.setDate(1,2,2008);

date2.setDate("February",2, 2008);

date3.setDate(2008);

System.out.println(date1);

System.out.println(date2);

System.out.println(date3);

}

------------------------------------------------<程式碼結束>--------------------------------------

主程式碼

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.Scanner;

public class DateFourthTry {

private int month, day, year;

public void setDate(int month, int day, int year) {

this.month = month;

this.day = day;

this.year = year;

}

public void setDate(String stringmonth, int day, int year){

this.month = monthString(stringmonth);

this.day = day;

this.year = year;

}

public void setDate(int year) {

setDate(1, 1, year);

}

public int monthString(String month){

if(month == "January")

return 1;

else if(month == "February")

return 2;

else if(month == "March")

return 3;

else if(month == "April")

return 4;

else if(month == "May")

return 5;

else if(month == "June")

return 6;

else if(month == "July")

return 7;

else if(month == "August")

return 8;

else if(month == "September")

return 9;

else if(month == "October")

return 10;

else if(month == "November")

return 11;

else if(month == "December")

return 12;

else {

System.out.println("Fatal Error");

System.exit(0);

return 0;

}

public String toString() {

return (month + " " + day + ", " + year);

}

public int getDay() {

return day;

}

public int getYear() {

return year;

}

public int getMonth() {

return month;

}

public boolean equals(DateFourthTry otherDate) {

return( (month == otherDate.month) && (day == otherDate.day) && (year == otherDate.year) );

}

public boolean precedes(DateFourthTry otherDate) {

return ( (year < otherDate.year) ||

(year == otherDate.year && getMonth() < otherDate.getMonth() ) ||

(year == otherDate.year && month == otherDate.month && day < otherDate.day) );

}

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附註：

Lab ADT

2009-04-27T21:39:00.000+08:00

Define a Complex class and write an object oriented program to compute (2+3i)+(4+5i) in Java.
The methods should include an access and a mutator.

class程式碼

------------------------------------------------<程式碼開始>--------------------------------------
public class ADTClass {

private int realNum = 0, imaginaryNum = 0;

public ADTClass(int realNum, int imaginaryNum) {

this.realNum = realNum;

this.imaginaryNum = imaginaryNum;

}

public ADTClass add(ADTClass f) {

ADTClass ans = new ADTClass(1, 1);

ans.realNum = this.realNum + f.realNum;

ans.imaginaryNum = this.imaginaryNum + f.imaginaryNum;

return ans;

}

public String toString() {

return realNum + "+" + imaginaryNum + "i";

}

------------------------------------------------<程式碼結束>--------------------------------------

主程式碼

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class ADT {

public static void main (String args[]) {

ADTClass f1, f2;

f1 = new ADTClass(2, 3);

f2 = new ADTClass(4, 5);

System.out.println("f1 = " + f1.toString());

System.out.println("f2 = " + f2.toString());

System.out.println("f1 + f2 = " + f1.add(f2).toString());

}

------------------------------------------------<程式碼結束>--------------------------------------

附註：

Class definition 3

2009-04-27T21:16:00.001+08:00

Do Display 4.7 (3rd, 2nd ed.) or 4.5 (1st ed.). Then use Display 4.8 to call 4.7.

Question
In Display 4.7, if the method setDate has the parameter as setDate(int month, int day, int year), what kind of changes should be made in its body of codes?

class程式碼

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.Scanner;

public class DateFourthTry {

private int month;

private int day;

private int year;

public void setDate(int month, int day, int year) {

this.month = month;

this.day = day;

this.year = year;

}

public String toString() {

return (month + " " + day + ", " + year);

}

public int getDay() {

return day;

}

public int getYear() {

return year;

}

public int getMonth() {

return month;

}

public boolean equals(DateFourthTry otherDate) {

return( (month == otherDate.month) && (day == otherDate.day) && (year == otherDate.year) );

}

public boolean precedes(DateFourthTry otherDate) {

return ( (year < otherDate.year) ||

(year == otherDate.year && getMonth() < otherDate.getMonth() ) ||

(year == otherDate.year && month == otherDate.month && day < otherDate.day) );

}

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主程式碼

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class Classdefinition3 {

public static void main (String args[]) {

DateFourthTry date1 = new DateFourthTry(), date2 = new DateFourthTry();

date1.setDate(6, 17, 1882);

date2.setDate(6, 17, 1882);

if(date1.equals(date2))

System.out.println(date1 + " equals " + date2);

else

System.out.print(date1 + " does not equals " + date2);

date1.setDate(7, 28, 1750);

if(date1.precedes(date2))

System.out.println(date1 + " comes before " + date2);

else

System.out.print(date2 + " comes before or is equal to " + date1);

}

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附註：

Homework 4-13-2009 Fraction Multiplication

2009-04-27T18:38:00.001+08:00

Write a program to implement a method that can multiply 2 fractions. You will implement a class called Fraction consisting of a numerator and a denominator. The multiplication of
2 fractions should be equal to a fraction.
Use 1/2 * 1/3 as the test.

Hints:
Fraction f1, f2;
f1.multiply(f2);

due date: 4/27/2009

class程式碼

------------------------------------------------<程式碼開始>--------------------------------------
public class Fractions {

private int numerator, denominator;

public Fractions(int numerator, int denominator) {

this.numerator = numerator;

this.denominator = denominator;

}

public Fractions add(Fractions f) {

int x, a, b;

Fractions ans = new Fractions(1, 1);

ans.numerator = f.denominator * this.numerator + f.numerator * this.denominator;

ans.denominator = f.denominator * this.denominator;

ans.numerator = ans.numerator / reduction (ans.numerator, ans.denominator);

ans.denominator = ans.denominator / reduction (ans.numerator, ans.denominator);

return ans;

}

public Fractions multiply(Fractions f) {

Fractions ans = new Fractions(1, 1);

ans.numerator = f.numerator * this.numerator;

ans.denominator = f.denominator * this.denominator;

ans.numerator = ans.numerator / reduction (ans.numerator, ans.denominator);

ans.denominator = ans.denominator / reduction (ans.numerator, ans.denominator);

return ans;

}

private int reduction(int a, int b) {

int x;

if(a<b) {

x = a;

a = b;

b = x;

}

while (b != 0) {

x = a % b;

a = b;

b = x;

}

return a;

}

public String toString()

{

return (numerator + "/" + denominator);

}

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主程式碼

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class Homework04132009FM {

public static void main (String args[]) {

Fractions f1, f2, f3, f4;

f1 = new Fractions(4, 2);

f2 = new Fractions(1, 3);

System.out.println("f1 = " + f1.toString());

System.out.println("f2 = " + f2.toString());

System.out.println("f1 + f2 = " + f1.add(f2).toString());

System.out.println("f1 * f2 = " + f1.multiply(f2).toString() + "\n");

f3 = new Fractions(5, 6);

f4 = new Fractions(2, 9);

System.out.println("f3 = " + f3.toString());

System.out.println("f4 = " + f4.toString());

System.out.println("f3 + f4 = " + f3.add(f4).toString());

System.out.println("f3 * f4 = " + f3.multiply(f4).toString() + "\n");

}

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附註：

lab Fraction equality test

2009-04-13T21:25:00.001+08:00

Write a program to implement a method that can check whether 2 fractions are equal. You will implement a class called Fraction consisting of a numerator and a denominator. The equality test of 2 fractions should return a boolean value.

Use the following as the tests.

* 1/2, 2/4
* 5/6, 6/7

Hints:
Fraction f1, f2;
f1.equals(f2);

class程式碼

------------------------------------------------<程式碼開始>--------------------------------------
public class Fraction {

private int numerator, denominator;

public Fraction(int numerator, int denominator) {

this.numerator = numerator;

this.denominator = denominator;

}

boolean equals(Fraction f) {

if(f.denominator * this.numerator - f.numerator * this.denominator == 0)

return true;

else

return false;

}

public String toString()

{

return (numerator + "/" + denominator);

}

------------------------------------------------<程式碼結束>--------------------------------------

主程式碼

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class Fractionequalitytest {

public static void main (String args[]) {

Fraction f1, f2;

f1 = new Fraction(1, 2);

f2 = new Fraction(2, 4);

System.out.println("f1 = " + f1.toString());

System.out.println("f2 = " + f2.toString());

if(f1.equals(f2))

System.out.println("f1 = f2\n");

else

System.out.println("f1 != f2\n");

f1 = new Fraction(5, 6);

f2 = new Fraction(6, 7);

System.out.println("f1 = " + f1.toString());

System.out.println("f2 = " + f2.toString());

if(f1.equals(f2))

System.out.println("f1 = f2\n");

else

System.out.println("f1 != f2\n");

}

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附註：

lab Fraction Addition

2009-04-13T20:45:00.001+08:00

Write a program to implement a method that can do additions of 2 fractions. You will implement a class called Fraction consisting of a numerator and a denominator. The additions of
2 fractions should be equal to a fraction.
Use 1/2+1/3 as the test.

Hints:
Fraction f1, f2;
f1.add(f2);

class程式碼

------------------------------------------------<程式碼開始>--------------------------------------
public class Fractions {

public int numerator, denominator;

Fractions(int numerator, int denominator) {

this.numerator = numerator;

this.denominator = denominator;

}

public void add(Fractions f) {

int numerators, denominators;

numerators = f.denominator * this.numerator + f.numerator * this.denominator;

denominators = f.denominator * this.denominator;

System.out.println(numerators + "/" + denominators);

}

------------------------------------------------<程式碼結束>--------------------------------------

主程式碼

------------------------------------------------<程式碼開始>--------------------------------------
import java.util.*;

public class FractionAddition {

public static void main (String args[]) {

Fractions f1, f2;

f1 = new Fractions(1, 2);

f2 = new Fractions(1, 3);

f1.add(f2);

}

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附註：本次lab的寫法只能滿足本題目的用法，對於需要持續相加時會有問題，解決用法請參考下個lab。

Homework 3-30-2009: counter

2009-04-13T17:17:00.000+08:00

Define a class called Counter whose objects count things. An object of this class records a count that is a nonnegative integer. Include methods to set the counter to 0, to increase the count by 1, and to decrease the count by 1. Include an accessor method that returns the current count value and a method that outputs the count to the screen. Write a program to test

counter.reset();
counter.inc();
counter.inc();
counter.dec();
counter.output();

class程式碼

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public class Counter

{

 public int count = 0;

 public void reset()

{

  count = 0;

}

 public void inc()

{

  count++;

}

 public void dec()

{

  count--;

}

 public void output()

{

  System.out.println(count);

}

}

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主程式碼

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import java.util.*;

public class Homework03302009Counter {

    public static void main (String args[]) {

        Counter counter = new Counter();

  counter.reset();

  counter.inc();

  counter.inc();

  counter.dec();

  counter.output();

}

}

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附註：

lab class definition 2

2009-03-31T01:57:00.000+08:00

Study Display 4.4 (2nd ed. and 3rd ed.) or Display 4.2 & Display 4.3 (1st ed.) and then
1. Comment out date.setDate(6, 17, year); by // date.setDate(6, 17, year);
2. At the next line below, add date.readInput();
3. Run the program again. Fix any problems you may encouter along the way.
4. At the last line of your program, add System.out.println(date.month);
and see what happens. Why?

執行過程

程式碼

class程式碼

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import java.util.Scanner;

public class DateThirdTry {

private String month;

private int day;

private int year;

public void setDate(int newMonth, int newDay, int newYear){

month = monthString(newMonth);

day = newDay;

year = newYear;

}

public String monthString(int monthNumber){

switch (monthNumber) {

case 1:

return "January";

case 2:

return "February";

case 3:

return "March";

case 4:

return "April";

case 5:

return "May";

case 6:

return "June";

case 7:

return "July";

case 8:

return "August";

case 9:

return "September";

case 10:

return "October";

case 11:

return "November";

case 12:

return "December";

default:

System.out.println("Fatal Error");

System.exit(0);

return "Error";

}

public void writeOutput(){

System.out.println(month + " " + day + ", " + year);

}

public void readInput(){

Scanner keyboard = new Scanner(System.in);

System.out.println("Enter month, day and year.");

System.out.println("Do not use a comma.");

month = keyboard.next();

day = keyboard.nextInt();

year = keyboard.nextInt();

}

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主程式碼

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import java.util.*;

public class class_definition_2 {

public static void main (String args[]) {

DateThirdTry date = new DateThirdTry();

int year = 1882;

//date.setDate(6, 17, year);

date.readInput();

date.writeOutput();

//System.out.println(date.month);

}

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附註：

lab class definition

2009-03-31T01:33:00.001+08:00

Study Display 4.1 and then do Self-Test Exercise 1.

class程式碼
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public class DateFirstTry {

public String month;

public int day;

public int year;

public void writeOutput()

{

System.out.println(month + " " + day + ", " + year);

}

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主程式碼
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import java.util.*;

public class Class_definition

{

public static void main (String args[])

{

DateFirstTry date1, date2;

date1 = new DateFirstTry();

date2 = new DateFirstTry();

date1.month = "December";

date1.day = 31;

date1.year = 2007;

System.out.println("date1:");

date1.writeOutput();

date2.month = "July";

date2.day = 4;

date2.year = 1776;

System.out.println("date2:");

date2.writeOutput();

}

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附註：今天上課完全被這段程式給打敗，只是一個小錯誤，讓我搞到整節課都跑不出來。
在class程式碼時把void寫成Void而無法判讀，而由於軟體的問題，在修改過後一直無法正確的編譯過去。

Homework: 3/23/2009

2009-03-25T20:50:00.000+08:00

Write a program to calculate average income by gender based on the following data, where F stands for female and M for male.

F 62,000
M 25,000
F 38,000
F 43,000
M 65,000
M 120,000
F 80,000
M 30,100

You should be able to allow users to type in a whole line such as F 80,000 followed by next line M 30,100.

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import java.util.*;

public class Homework03232009 {

public static void main (String args[]) {

Scanner Keyboard = new Scanner(System.in);

int mn=0, fn=0, le=1;

double mTotal=0, fTotal=0;

String sex;

do{

System.out.print("enter:");

sex = Keyboard.next();

if(sex.equals("M")){

mTotal = Keyboard.nextDouble();

mn++;

}

else if(sex.equals("F")){

fTotal = Keyboard.nextDouble();

fn++;

}

else if(sex.equals("exit")){

System.out.println("End");

le = 0;

}

else

System.out.println("error.\n");

}while(le==1);

System.out.println("Total people: " + (mTotal + fTotal));

System.out.println("Male's Avg = " + mTotal/mn);

System.out.println("Female's Avg = " + fTotal/fn);

}

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附註：本次也是參考以繳交之同學作業改寫，新增了偵錯輸入這部份。這次學到更多的字串應用方式。

Lab Cosine

2009-03-24T01:06:00.000+08:00

Write a Java program to calculate the triangular function as follows:
Cos(x)=1 - x ² /2!+ x⁴/4!- x⁶/ 6!...

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import java.util.*;

import java.util.Scanner;

public class Cosine {

public static void main (String args[]) {

Scanner Keyboard = new Scanner(System.in);

int x, n=0, i;

double answer=1, up=1, down=1;

System.out.print("Cos(x)=1 - x^2/2! + x^4/4! - x^6/6!...\nx:");

x = Keyboard.nextInt();

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

n = Keyboard.nextInt();

n*=2;

for(i=2 ; i<n+1 ; i+=2){

up = (-1) * up * x * x;

down = down * (i-1) * i;

answer = answer + up / down;

}

System.out.println("Cos(" + x + ") = " + answer);

}

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附註：本次程式碼是參考同學的方法來寫，因為發覺自己原本的方式太複雜了。

Lab Fibonacci

2009-03-23T20:49:00.003+08:00

List the first 100 numbers and the ratio of
a number to its previous number, such as ¹/₁ = 1, ²/₁ = 2, ³/₂ = 1·5,⁵/₃ = 1·666..., ⁸/₅ = 1·6, ¹³/₈ = 1·625, ²¹/₁₃ = 1·61538....

Want to know more about Fibonacci number

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import java.util.*;

public class Fibonacci {

public static void main (String args[]) {

int n;

double a=0, b=1, f=0;

System.out.println("Fibonacci List:");

for(n=1; n<101; n++){

f = a + b;

System.out.println("n = " + n + " => \t" + f + " => " + f/a);

b = a;

a = f;

}

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附註：本程式碼經過老師的提點，將不必要的判斷式給拿掉改寫。

Homework 3-16-2009

2009-03-19T22:21:00.006+08:00

1. Project 7 of Chap. 3
2. Write a program to generate the following table of arithmetic expressions

1*1=1 1*2=2 1*3=3 ... 1*9=9
2*1=2 2*2=4 2*3=6 ... 2*9=19
...
9*1=9 9*2=18 9*3=27 ... 9*9=81

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import java.util.*;

import java.util.Scanner;

public class Homework03162009{

static double Function(int x, int n){

double i, j=1, k, h, answer=0;

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

for(k=0, h=1;k<i;k++){

h = h * (k+1);

}

answer = answer + (Math.pow(x, i)) / h;

}

return answer + 1;

}

public static void main (String args[]) {

Scanner Keyboard = new Scanner(System.in);

int x;

System.out.println("Find e^x.");

System.out.println("e^x = 1 + x^2/2! + ... + x^n/n!\nenter x");

x = Keyboard.nextInt();

System.out.println("n = 1, e^" + x + " = " + Function(x, 1));

System.out.println("n = 10, e^" + x + " = " + Function(x, 10));

System.out.println("n = 50, e^" + x + " = " + Function(x, 50));

System.out.println("n = 100, e^" + x + " = " + Function(x, 100));

}

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附註：這部份程式碼驗證部份不知怎麼做，但是就程式來說應該沒有錯誤，若有問題請給予指教。
程式碼修正中...... 2009/03/20

2.

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import java.util.*;

public class Homework03162009 {

public static void main (String args[]) {

for(int i=1;i<=9;i++)

{

for(int j=1;j<=9;j++)

{

if(i*j>=10)

System.out.print(i+"X"+j+"="+i*j+" ");

else

System.out.print(i+"X"+j+"= "+i*j+" ");

}

System.out.println();

}

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附註：久久九九乘法算是基礎的程式練習題目，這部份比較大的問題應該屬於排版吧！因為如果沒有調整看起來會不整齊。

後來發現使用/t的方式即可定位好來，這樣就不必另外寫判斷式。