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Java基础程序编写(超详细超全)

Java基础程序编写(超详细超全)

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Java基础程序编写(超详细超全)

当您的机器上配置起了一个Java开发环境——您将使用一个“开发环境”来“开发”(编写)程序,那么接下来我们就开始编写一些基础却实用的程序,大家要多多练习,以达到熟练程度,再接下去学习更高级的编辑。老实说,我现在虽然是IT行业老大了,但是谁知道我当初背后的艰辛?反复敲了不知多少遍,键盘都坏了多少个。。。绝不是夸张。

1百分制分数到等级分数

packagepm;

publicclassSwitchTest{

//编写程序,实现从百分制分数到等级分数的转换

//

//>=90A

//80~89B

//70~79C

//60~69D

//<60E

publicstaticvoidmain(String[]args){

ints=87;

switch(s/10){

case10:System.out.println("A");break;

case9:System.out.println("A");break;

case8:System.out.println("B");break;

case7:System.out.println("c");break;

case6:System.out.println("D");break;

default:System.out.println("E");break;

}

}

}

2成法口诀阵形

packagepm;

publicclassSwitchTest{

publicstaticvoidmain(String[]args){

for(inti=1;i<=9;i++){

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

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

}

System.out.println();

}

}

}

3华氏和摄氏的转换法

packagepm;

importjava.util.Scanner;

publicclassSwitchTest{

publicstaticvoidmain(String[]args){

Scannersc=newScanner(System.in);

while(true){

System.out.println("请输入要转换的温度类型:C或F");

Strings=sc.next().trim();

if("c".equalsIgnoreCase(s)){

//做摄氏向华摄的转换

System.out.println("请输入要转换摄氏的温度:..");

doubledb=sc.nextDouble();

doubledb2=(db*9/5)+32;

System.out.println("对应的华氏温度:"+db2+"F");

}elseif("f".equalsIgnoreCase(s)){

//做华摄向摄氏的转换

System.out.println("请输入要转换华氏的温度:..");

doubledb=sc.nextDouble();

doubledb2=(db-32)*5/9;

System.out.println("对应的摄氏温度:"+Math.round(db2)+"C");

}elseif("exit".equalsIgnoreCase(s)){

break;

}

}

}

}

packagepm;

importjava.util.Scanner;

publicclassSwitchTest{

publicstaticvoidmain(String[]args){

Scannersc=newScanner(System.in);

booleanflag=true;

while(flag){

System.out.println("请输入要转换的温度,如:50c或100f");

Stringstr=sc.nextLine().trim();

if(str.endsWith("c")||str.endsWith("C")){

//做摄氏向华摄的转换30c

Stringst=str.substring(0,str.length()-1);

doubledb=Double.parseDouble(st);//[0,2)

//2doubledb=Double.valueOf(st).doubleValue();

doubledb2=(db*9/5)+32;

System.out.println("对应的华氏温度:"+db2+"F");

}elseif(str.endsWith("f")||str.endsWith("F")){

//做华摄向摄氏的转换

Stringst=str.substring(0,str.length()-1);

doubledb=Double.parseDouble(st);//[0,2)

//2doubledb=Double.valueOf(st).doubleValue();

doubledb2=(db-32)*5/9;

System.out.println("对应的摄氏温度:"+Math.round(db2)+"C");

}elseif("exit".equalsIgnoreCase(str)){

flag=false;

}

}

}

}

4三个数的最大数

packagepm;

publicclassSwitchTest{

publicstaticvoidmain(String[]args){

inta=1,b=2,c=3,d=0;

d=a>b?a:b;

d=a>b?(a>c?a:c):(b>c?b:c);

System.out.println("最多数为:"+d);

}

}

5简单计算器的小程序

packageone;

importjava.awt.BorderLayout;

importjava.awt.GridLayout;

importjava.awt.event.ActionEvent;

importjava.awt.event.ActionListener;

importjavax.swing.JButton;

importjavax.swing.JFrame;

importjavax.swing.JPanel;

importjavax.swing.JTextField;

publicclassJsqimplementsActionListener{

privateJFrameframe;

privateJButton[]bus;

privateJTextFieldjtx;

privateJButtonbu;

privatechar[]strs;

privateStringd_one="";

privateStringoperator;

publicstaticvoidmain(String[]args){

newJsq();

}

/*利用构造进行实例化*/

publicJsq(){

frame=newJFrame("计算器");

jtx=newJTextField(14);

bus=newJButton;

strs="789/456*123-0.+=".toCharArray();

for(inti=0;i<16;i++){

bus[i]=newJButton(strs[i]+"");

bus[i].addActionListener(this);

}

bu=newJButton("C");

bu.addActionListener(this);

init();

}

/*GUI初始化*/

publicvoidinit(){

JPaneljp1=newJPanel();

jp1.add(jtx);

jp1.add(bu);

frame.add(jp1,BorderLayout.NORTH);

JPaneljp2=newJPanel();

jp2.setLayout(newGridLayout(4,4));

for(inti=0;i<16;i++){

jp2.add(bus[i]);

}

frame.add(jp2,BorderLayout.CENTER);

frame.pack();

frame.setLocation(300,400);

frame.setVisible(true);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

/*事件的处理*/

publicvoidactionPerformed(ActionEventarg0){

/*获取输入字符*/

Stringconn=arg0.getActionCommand();

/*清除计算器内容*/

if("C".equals(conn)){

d_one="";

operator="";

jtx.setText("");

return;

}

/*暂未实现该功能*/

if(".".equals(conn)){

return;

}

/*记录运算符,保存运算数字*/

if(("+-*/".indexOf(conn))!=-1){

if("".equals(d_one)&&"".equals(jtx.getText()))return;

d_one=jtx.getText();

operator=conn;

jtx.setText("");

return;

}

/*计算结果*/

if("=".equals(conn)){

if("".equals(d_one)&&"".equals(jtx.getText()))return;

doubledb=0;

if("+".equals(operator)){

db=Double.parseDouble(d_one)

+Double.parseDouble(jtx.getText());

jtx.setText(db+"");

}

if("-".equals(operator)){

db=Double.parseDouble(d_one)

-Double.parseDouble(jtx.getText());

jtx.setText(db+"");

}

if("*".equals(operator)){

db=Double.parseDouble(d_one)

*Double.parseDouble(jtx.getText());

jtx.setText(db+"");

}

if("/".equals(operator)){

db=Double.parseDouble(d_one)

/Double.parseDouble(jtx.getText());

jtx.setText(db+"");

}

d_one=db+"";

return;

}

//界面显示

jtx.setText(jtx.getText()+conn);

}

}

6三角形图案

packagepm;

publicclassSwitchTest{

publicstaticvoidmain(String[]args){

intn=5;

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

for(intj=0;j

System.out.print("");

}

for(intk=0;k<2*i-1;k++){

System.out.print("*");

}

System.out.println();

}

}

}

7输出输入的姓名

packagepm;

importjava.util.Scanner;

publicclassSwitchTest{

publicstaticvoidmain(String[]args){

Stringname=null;

Scannersca=newScanner(System.in);

charfirstChar;

do{

System.out.println("pleaseinputyourname");

name=sca.nextLine();

firstChar=name.charAt(0);

}while(!(firstChar>='a'&&firstChar<='z'||

firstChar>='A'&&firstChar<='Z'));

System.out.println("OK!yournameis:"+name);

}

}

8一小时倒计时小程序

packagepm;

importjavax.swing.JFrame;

importjavax.swing.JLabel;

importjavax.swing.JPanel;

publicclassSwitchTest{

privateJFrameframe;

privateJLabeljl1;

privateJLabeljl2;

privateJLabeljl3;

/*主方法*/

publicstaticvoidmain(String[]args){

newSwitchTest().getTime();

}

/*倒计时的主要代码块*/

privatevoidgetTime(){

longtime=1*3600;

longhour=0;

longminute=0;

longseconds=0;

while(time>=0){

hour=time/3600;

minute=(time-hour*3600)/60;

seconds=time-hour*3600-minute*60;

jl1.setText(hour+"时");

jl2.setText(minute+"分");

jl3.setText(seconds+"秒");

try{

Thread.sleep(1000);

}catch(InterruptedExceptione){

e.printStackTrace();

}

time--;

}

}

/*构造实现界面的开发GUI*/

publicSwitchTest(){

frame=newJFrame("倒计时");

jl1=newJLabel();

jl2=newJLabel();

jl3=newJLabel();

init();

}

/*组件的装配*/

privatevoidinit(){

JPaneljp=newJPanel();

jp.add(jl1);

jp.add(jl2);

jp.add(jl3);

frame.add(jp);

frame.setVisible(true);

frame.setLocation(300,400);

frame.setSize(300,200);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

}

9棋盘图案

publicclassSjx{

publicstaticvoidmain(String[]args){

intSIZE=19;

for(inti=0;i

if(i<10){

System.out.print(""+i);//两个空格

}else{

System.out.print(""+(char)(i+'a'-10));//两个空格

}

}

System.out.println();

// System.out.print(i<10?(char)(i+'0'):(char)(i+'a'-10));

for(inti=0;i

if(i<10){

System.out.print(i+"");//一个空格

}else{

System.out.print((char)(i+'a'-10)+"");//一个空格

}

for(intj=0;j

System.out.print("*"+"");//两个空格

}

System.out.println();

}

}

}

10数组输出唐诗

packageday04;

publicclassArrayTest{

publicstaticvoidmain(String[]args){

char[][]arr=newchar;

Strings="朝辞白帝彩云间千里江陵一日还两岸猿声啼不住轻舟已过万重山";

for(inti=0;i

for(intj=0;j

arr[i][j]=s.charAt(i*7+j);

}

}

for(inti=0;i

for(intj=0;j

System.out.print(arr[arr.length-j-1][i]+"");

}

System.out.println();

}

}

}

11找出满足条件的最小数

packageday02;

publicclassFangk{

publicstaticvoidmain(String[]args){

// for(inti=1000;i<=9999;i++){

// intq=i/1000;

// intb=i/100%10;

// ints=i/10%10;

// intg=i%10;

// if(q>b&&s>g&&q+g==b+s&&b%2!=0){

// System.out.println("TheMinNumberis:"+i);

// break;

// }

// }

loop1: for(intq=1;q<=9;q++){

loop2: for(intb=0;b<=9;b++){

if(b%2==0){

continueloop2;

}

for(ints=0;s<=9;s++){

for(intg=0;g<=9;g++){

if(q>b&&s>g&&q+g==b+s){

System.out.println("TheMinNumberis:"+(q*1000+b*100+s*10+g));

breakloop1;

}

}

}

}

}

}

}

12判断一个数是否是素数

packageday02;

publicclassFangk{

publicstaticvoidmain(String[]args){

intnum=14;

booleanflag=true;

for(inti=2;i<=num/2;i++){

if(num%i==0){

flag=false;

break;

}

}

if(flag){

System.out.println(num+"isaprimenumber!");

}else{

System.out.println(num+"isnotaprimenumber!");

}

}

}

//////////////////////////////////////////////////////////////////////

packageday04;

importjava.util.Scanner;

publicclassA1{

publicstaticvoidmain(String[]args){

intn;

Scannersca=newScanner(System.in);

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

n=sca.nextInt();

if(isPrimeNumber(n)){

System.out.println(n+"isaprimenumber!");

}else{

System.out.println(n+"isnotaprimenumber!");

}

}

publicstaticbooleanisPrimeNumber(intn){

for(inti=2;i<=n/2;i++){

if(n%i==0){

returnfalse;

}

}

returntrue;

}

}

12判断一个数是否是素数

packageday02;

publicclassFangk{

publicstaticvoidmain(String[]args){

intnum=14;

booleanflag=true;

for(inti=2;i<=num/2;i++){

if(num%i==0){

flag=false;

break;

}

}

if(flag){

System.out.println(num+"isaprimenumber!");

}else{

System.out.println(num+"isnotaprimenumber!");

}

}

}

//////////////////////////////////////////////////////////////////////

packageday04;

importjava.util.Scanner;

publicclassA1{

publicstaticvoidmain(String[]args){

intn;

Scannersca=newScanner(System.in);

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

n=sca.nextInt();

if(isPrimeNumber(n)){

System.out.println(n+"isaprimenumber!");

}else{

System.out.println(n+"isnotaprimenumber!");

}

}

publicstaticbooleanisPrimeNumber(intn){

for(inti=2;i<=n/2;i++){

if(n%i==0){

returnfalse;

}

}

returntrue;

}

}

14将一个整数以二进制输出

packageday04;

importjava.util.Scanner;

publicclassArrayTest{

publicstaticvoidmain(String[]args){

intn;

Scanners=newScanner(System.in);

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

n=s.nextInt();

for(inti=31;i>=0;i--){

if((n&(1<

System.out.print("1");

}else{

System.out.print("0");

}

if((32-i)%8==0){

System.out.print("");

}

}

}

}

15矩形图案

packageday02;

publicclassFangk{

publicstaticvoidmain(String[]args){

intm=5,n=6;

for(inti=0;i

System.out.print("*");

}

System.out.println();

for(inti=0;i

System.out.print("*");

for(intj=0;j

System.out.print("");

}

System.out.print("*");

System.out.println();

}

for(inti=0;i

System.out.print("*");

}

}

}