Java基础程序编写（超详细超全）
1、1百分制分数到等级分数
package pm;
public class SwitchTest {
//编写程序，实现从百分制分数到等级分数的转换
//
//>=90 A
// 80~89 B
// 70~79 C
// 60~69 D
// <60 E
public static void main(String[] args) {
int s=87;
switch(s/10){
case 10 :System.out.println("A");break;
case 9 :System.out.println("A");break;
case 8 :System.out.println("B");break;
case 7 :System.out.println("c");break;
case 6 :System.out.println("D");break;
default :System.out.println("E");break;
}
}
}
2、2成法口诀阵形
package pm;
public class SwitchTest{
public static void main(String[] args){
for(int i=1;i<=9;i++){
for(int j=1;j<=i;j++){
System.out.print(j+"*"+i+"="+(i*j)+"\t");
}
System.out.println();
}
}
}
3、3华氏和摄氏的转换法
package pm;
import java.util.Scanner;
public class SwitchTest {
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
while (true) {
System.out.println("请输入要转换的温度类型：C 或 F");
String s = 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:..");
double db = sc.nextDouble();
double db2 = (db * 9 / 5) + 32;
System.out.println("对应的华氏温度：" + db2 + "F");
} else if ("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:..");
double db = sc.nextDouble();
double db2 = (db - 32) * 5 / 9;
System.out.println("对应的摄氏温度：" + Math.round(db2) + "C");
}else if("exit".equalsIgnoreCase(s)){
break;
}
}
}
}
package pm;
import java.util.Scanner;
public class SwitchTest{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
boolean flag=true;
while (flag) {
System.out.println("请输入要转换的温度,如：50c或100f");
String str = sc.nextLine().trim();
if (str.endsWith("c") || str.endsWith("C")) {
//做摄氏向华摄的转换 30c
String st = str.substring(0, str.length() - 1);
double db = Double.parseDouble(st);//[0,2)
//2 double db=Double.valueOf(st).doubleValue();
double db2 = (db * 9 / 5) + 32;
System.out.println("对应的华氏温度：" + db2 + "F");
} else if (str.endsWith("f") || str.endsWith("F")) {
//做华摄向摄氏的转换
String st = str.substring(0, str.length() - 1);
double db = Double.parseDouble(st);//[0,2)
//2 double db=Double.valueOf(st).doubleValue();
double db2 = (db - 32) * 5 / 9;
System.out.println("对应的摄氏温度：" + Math.round(db2) + "C");
}else if("exit".equalsIgnoreCase(str)){
flag=false;
}
}
}
}
4、4三个数的最大数
package pm;
public class SwitchTest {
public static void main(String[] args) {
int a=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、5简单计算器的小程序
package one;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class Jsq implements ActionListener {
private JFrame frame;
private JButton[] bus;
private JTextField jtx;
private JButton bu;
private char[] strs;
private String d_one = "";
private String operator;
public static void main(String[] args) {
new Jsq();
}
/* 利用构造进行实例化 */
public Jsq() {
frame = new JFrame("计算器");
jtx = new JTextField(14);
bus = new JButton[16];
strs = "789/456*123-0.+=".toCharArray();
for (int i = 0; i < 16; i++) {
bus[i] = new JButton(strs[i] + "");
bus[i].addActionListener(this);
}
bu = new JButton("C");
bu.addActionListener(this);
init();
}
/* GUI 初始化 */
public void init() {
JPanel jp1 = new JPanel();
jp1.add(jtx);
jp1.add(bu);
frame.add(jp1, BorderLayout.NORTH);
JPanel jp2 = new JPanel();
jp2.setLayout(new GridLayout(4, 4));
for (int i = 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 */
public void actionPerformed(ActionEvent arg0) {
/*获取输入字符*/
String conn = 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;
double db = 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、6三角形图案
package pm;
public class SwitchTest{
public static void main(String[] args){
int n=5;
for(int i=0;i<=n;i++){
for(int j=0;j<n-i;j++){
System.out.print(" ");
}
for(int k=0;k<2*i-1;k++){
System.out.print("*");
}
System.out.println();
}
}
}
7、7输出输入的姓名
package pm;
import java.util.Scanner;
public class SwitchTest{
public static void main(String[] args){
String name=null;
Scanner sca=new Scanner (System.in);
char firstChar;
do{
System.out.println("please input your name");
name=sca.nextLine();
firstChar=name.charAt(0);
}while(!(firstChar>='a' && firstChar<='z' ||
firstChar>='A' && firstChar<='Z'));
System.out.println("OK! your name is:"+name);
}
}
8、8一小时倒计时小程序
package pm;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class SwitchTest {
private JFrame frame;
private JLabel jl1;
private JLabel jl2;
private JLabel jl3;
/*主方法*/
public static void main(String[] args) {
new SwitchTest().getTime();
}
/*倒计时的主要代码块*/
private void getTime(){
long time=1*3600;
long hour =0 ;
long minute =0 ;
long seconds=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 (InterruptedException e) {
e.printStackTrace();
}
time--;
}
}
/*构造 实现界面的开发 GUI */
public SwitchTest(){
frame = new JFrame("倒计时");
jl1 = new JLabel();
jl2 = new JLabel();
jl3 = new JLabel();
init();
}
/*组件的装配*/
private void init(){
JPanel jp=new JPanel();
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、9棋盘图案
public class Sjx{
public static void main(String[] args){
int SIZE=19;
for(int i=0;i<SIZE;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(int i=0;i<SIZE;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(int j=0;j<SIZE;j++){
System.out.print("*"+" ");//两个空格
}
System.out.println();
}
}
}
10、10数组输出唐诗
package day04;
public class ArrayTest {
public static void main(String[] args){
char[][] arr=new char[4][7];
String s="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(int i=0;i<arr.length;i++){
for(int j=0;j<arr[i].length;j++){
arr[i][j]=s.charAt(i*7+j);
}
}
for(int i=0;i<arr[0].length;i++){
for(int j=0;j<arr.length;j++){
System.out.print(arr[arr.length-j-1][i]+" ");
}
System.out.println();
}
}
}
11、11找出满足条件的最小数
package day02;
public class Fangk{
public static void main(String[] args){
// for(int i=1000;i<=9999;i++){
// int q=i/1000;
// int b=i/100%10;
// int s=i/10%10;
// int g=i%10;
// if(q>b && s>g && q+g==b+s && b%2!=0){
// System.out.println("The Min Number is:"+i);
// break;
// }
// }
loop1: for(int q=1;q<=9;q++){
loop2: for(int b=0;b<=9;b++){
if(b%2==0){
continue loop2;
}
for(int s=0;s<=9;s++){
for(int g=0;g<=9;g++){
if(q>b && s>g && q+g==b+s){
System.out.println("The Min Number is:"+(q*1000+b*100+s*10+g));
break loop1;
}
}
}
}
}
}
}
12、12判断一个数是否是素数
package day02;
public class Fangk{
public static void main(String[] args){
int num=14;
boolean flag=true;
for(int i=2;i<=num/2;i++){
if(num%i==0){
flag=false;
break;
}
}
if(flag){
System.out.println(num+" is a prime number!");
}else{
System.out.println(num+" is not a prime number!");
}
}
}
//////////////////////////////////////////////////////////////////////
package day04;
import java.util.Scanner;
public class A1{
public static void main(String[] args){
int n;
Scanner sca=new Scanner(System.in);
System.out.println("please input a number:");
n=sca.nextInt();
if(isPrimeNumber(n)){
System.out.println(n+"is a prime number!");
}else{
System.out.println(n+"is not a prime number!");
}
}
public static boolean isPrimeNumber(int n){
for(int i=2;i<=n/2;i++){
if(n%i==0){
return false;
}
}
return true;
}
}
13、12判断一个数是否是素数
package day02;
public class Fangk{
public static void main(String[] args){
int num=14;
boolean flag=true;
for(int i=2;i<=num/2;i++){
if(num%i==0){
flag=false;
break;
}
}
if(flag){
System.out.println(num+" is a prime number!");
}else{
System.out.println(num+" is not a prime number!");
}
}
}
//////////////////////////////////////////////////////////////////////
package day04;
import java.util.Scanner;
public class A1{
public static void main(String[] args){
int n;
Scanner sca=new Scanner(System.in);
System.out.println("please input a number:");
n=sca.nextInt();
if(isPrimeNumber(n)){
System.out.println(n+"is a prime number!");
}else{
System.out.println(n+"is not a prime number!");
}
}
public static boolean isPrimeNumber(int n){
for(int i=2;i<=n/2;i++){
if(n%i==0){
return false;
}
}
return true;
}
}
14、14将一个整数以二进制输出
package day04;
import java.util.Scanner;
public class ArrayTest {
public static void main(String[] args){
int n;
Scanner s=new Scanner(System.in);
System.out.println("please input a number:");
n=s.nextInt();
for(int i=31;i>=0;i--){
if((n&(1<<i))!=0){
System.out.print("1");
}else{
System.out.print("0");
}
if((32-i)%8==0){
System.out.print(" ");
}
}
}
}
15、15矩形图案
package day02;
public class Fangk {
public static void main(String[] args){
int m=5,n=6;
for(int i=0;i<n;i++){
System.out.print("* ");
}
System.out.println();
for(int i=0;i<m-2;i++){
System.out.print("* ");
for(int j=0;j<n-2;j++){
System.out.print(" ");
}
System.out.print("*");
System.out.println();
}
for(int i=0;i<n;i++){
System.out.print("* ");
}
}
}