第九次Java作业

1.编写一个方法，

public class test {
public static void mppx(){
    Scanner input = new Scanner(System.in);
     int a[] = new int[4];
for(int i=0;i<a.length;i++){
    a[i]=input.nextInt();
     }
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]){
            int max=a[j];
            a[j]=a[j+1];
            a[j+1]=max;
             }
          }
      }
for (int i = 0; i < a.length; i++) {
    System.out.println(a[i]);
           }
       }
public static void main(String[] args) {
   mppx();
         }

}

 

 2编写一个方法，求n的阶乘

冒泡排序（由小到大），并调用该方法

public class test {
    public static int j(int n) {
        int sum = 1;
        for (int i = 1; i <= n; i++) {
            sum = sum * i;
        }
        return sum;
    }

    public static void main(String[] args) {
        System.out.println("阶乘为" + j(6));
    }3.编写一个方法，判断该年份是平年还是闰年。[必做题]

 

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package homework9;

public class Test3 {

     public static int pr(int n){
            if(n%4==0&&n%100!=0||n%400==0)
                System.out.println("是闰年");
            else
                System.out.println("是平年");
            return n;
          }

        public static void main(String[] args){
            System.out.println(pr(2020));

    }

}

 

 4.课堂没完成的menu菜单，实现幸运抽奖功能

package task;

import java.util.Random;
import java.util.Scanner;

public class T1 {

     public static void main(String[] args) {
         mainMenu();
}
    public static void mainMenu() {
        Scanner input = new Scanner(System.in);
        System.out.println("欢迎使用本系统");
        System.out.println("1.登录");
        System.out.println("2.注册");
        System.out.println("3.幸运抽奖.");
        System.out.println("4.退出系统");
        System.out.println("请选择");
        int i = input.nextInt();
        switch (i) {
        case 1:
            login();
            break;
        case 2:
            zhuce();
            break;
        case 3:
            xingyuncj();
            break;
        case 4:
            tuichu();
            break;
            
        }
    }

    public static void login() {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.println("输入用户名");
        String uname = input.next();
        System.out.println("输入密码");
        String upwd = input.next();
        if (uname.equals("zs") && upwd.equals("123")) {
            System.out.println("登录成功");
        } else {
            System.out.println("登录失败");
        }
        returnMain();
    
    }
    public static void zhuce() {
        Scanner input = new Scanner(System.in);
        System.out.println("用户名");
        String uname = input.next();
        System.out.println("密码");
        String upwd = input.next();
        if(uname.equals(null) || upwd.equals(null) ) {
            System.out.println("注册失败");
        }else {
            System.out.println("注册成功");
        }
        returnMain();
    }
  
    public static void xingyuncj() {
         Scanner input = new Scanner(System.in);
         System.out.println("幸运抽奖");
         System.out.println("输入会员号");
         int a=input.nextInt();
         Random i=new Random();
         int b=i.nextInt(10);
         if(a==b) {
             System.out.println("恭喜中奖");
         }
         else
         {
             System.out.println("未中奖");
         }
         returnMain();
    }
  
   
   

    public static void tuichu() {
        System.out.println("是否退出系统Y/N");
        Scanner input = new Scanner(System.in);
        String a = input.next();
        if(a.equalsIgnoreCase("y")) {
            System.out.println("退出系统成功");
        }else {
            returnMain();
        }
    } 
    
    public static void returnMain(){
        System.out.println("是否返回主菜单?Y/N");
        Scanner input = new Scanner(System.in);
        if (input.next().equalsIgnoreCase("Y")) {
            mainMenu();
        }else{
            System.out.println("谢谢使用");
        }

    }
}