Java基础程序编写(超详细超全)
的有关信息介绍如下: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("*"); } } }