JAVA初级练习代码

package com.hyjy.lxt;

import java.util.Scanner;

import java.util.Random;

import java.util.Calendar;

public class LiXi4_2 {

public static void main(String[] args) {

输入一个年份判断是不是闰年

Scanner in = new Scanner(System.in);

System.out.println(请输入年份：);

int year = in.nextInt();

if (year % 4 == 0 && year % 100 == 0 year % 400 == 0){ System.out.println(这是闰年);

}

else{

System.out.println(这不是闰年);

}

switch语句的应用

Scanner in = new Scanner(System.in);

System.out.println(请输入今天周几：);

int day = in.nextInt();

switch(day){

case 1System.out.println(上班第一天);break;

case 2System.out.println(无聊);break;

case 3System.out.println(难熬);break;

case 4System.out.println(快到周末了);break;

case 5System.out.println(胜利就在眼前);break;

case 6System.out.println(睡一天);break;

case 7System.out.println(再睡一天);break;

default System.out.println(输入错误);

}

猜数字

Scanner in = new Scanner(System.in);

Random ran = new Random();

int x = ran.nextInt(100);

System.out.println(请输入你猜的数字（100以内整数）：);

int y = in.nextInt();

while(true){

if(x == y){

System.out.println(猜对了结束);

break;

}

else if(x y){

System.out.println(猜大了重新猜);

y = in.nextInt();

continue;

}

else {

System.out.println(猜小了重新猜);

y = in.nextInt();

continue;

}

}

超市收银系统

Scanner in = new Scanner(System.in);

System.out.println();

System.out.println( 欢迎光临乐超市); System.out.println();

System.out.println(商品编号：1.白银10 2.黄金12 3.钻石20 ); System.out.println(请输入商品编号：);

int number = in.nextInt();

System.out.println(请输入商品数量：);

int count = in.nextInt();

double money;

while(true) {

if(number == 1){

money = 10 count;

break;}

else if(number == 2){

money = 12 count;

break;}

else if(number == 3){

money = 20 count;

break;}

else{

System.out.println(编号输入错误请重新输入);

number = in.nextInt();

continue;

}

}

System.out.println(请输入实收金额);

int cash = in.nextInt();

while (true){

if(cash money){

System.out.println(金额输入错误，请重新输入：);

cash = in.nextInt();

continue;

}

else{

System.out.println(找零+ (cash - money));

break;

}

}

定义和遍历一维数组

int[] a = new int[]{1,2,3,4};

for (int i = 0;i a.length;i++){

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

}

定义遍历二维数组

int[][] a = new int[][]{{1,2,3},{4,5,6}};

int i,j;

for( i = 0;i a.length;i++){

for( j = 0;j a[i].length;j++){

System.out.println(a[i][j]);

}

j = 0;

}

冒泡排序

int x = 0;

int[] a = new int[]{1,23,43,234,12,20};

for(int i = 0;i a.length-1;i++){

for(int j = 0;j a.length - 1 - i;j++){

if(a[j] a[j + 1]){

x = a[j];

a[j] = a[j + 1];

a[j + 1] = x;

}

}

}

for(int ya)

System.out.println(y);

从控制台接收两个数字计算它们的公约数Scanner in = new Scanner(System.in);

System.out.println(请输入两个数字：);

int x = in.nextInt();

int y = in.nextInt();

if(x y){

int a;

a = x;

x = y;

y = a;

while(x % y != 0){

int b;

b = x % y;

x = y;

y = b;

}

System.out.println(这两个数字的最大公约数是+ y);

}else

{

while(x % y != 0){

int b;

b = x % y;

x = y;

y = b;

}

System.out.println(这两个数字的最大公约数是+ y);

}

创建一个整数数组，数组大小随机产生，数组里的整数也是随机产生的1-1000之间的整数

Random ran = new Random();

int x = ran.nextInt(100);

int[] a =new int[x];

for (int i = 0;i x - 1;i++){

a[i] = ran.nextInt(100);

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

}

通过数组输出九九乘法表

int[] a = new int[]{1,2,3,4,5,6,7,8,9};

int i,j;

for (i = 0; i 9;i++){

for(j = 0;j = i;j++){

System.out.print(a[i] + + a[j] + = + a[i]a[j] + t);

}

System.out.println();

}

计算15的阶乘

int i,a=1;

for(i = 1;i 16;i++){

a = a i;

}

System.out.println(a);

输出当前的日期时间

Calendar in = Calendar.getInstance();

int mouth = in.get(Calendar.MONTH) + 1;

int day = in.get(Calendar.DATE);

int year = in.get(Calendar.YEAR);

int hou = in.get(Calendar.HOUR);

int min = in.get(Calendar.MINUTE);

System.out.println(year + 年+ mouth + 月+ day + 日+ hou + 时+ min +分);

不用数组普通方式输出九九乘法表

int i,j;

for (i = 1;i 10;i++){

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

System.out.print(i + + j + = + ij + t);

}

System.out.println();

}

等本金还款贷款18万分60个月还清年利率5.6% 输出每月所还本金利息本金+利息

int i;

Scanner in = new Scanner(System.in);

System.out.println(请输入贷款本金);

double dai = in.nextDouble();

double li ;

double ben;

double zong;

for(i = 1 ;i 61;i++){

ben = dai(61-i);

li = dai (0.05612);

dai = dai- ben;

System.out.println(第+ i + 个月应还本金：+ ben + 元);

System.out.println(第+ i + 个月应还利息：+ li + 元);

System.out.println(第+ i + 个月应还本金+利息：+ (li + ben) + 元);

System.out.println();

} }