5.7 第十周java作业

1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

import java.util.Scanner;

public class zuoye {
     public static void mppx(int []x) {
         for (int i = 0; i < x.length; i++) {
             for(int j=0;j<x.length;j++){
              if (x[i]<x[j]) {
               int temp=x[i];
               x[i]=x[j];
                x[j]=temp;
               }
           }

       }
    }
     public static void main(String[] args){
        Scanner input=new Scanner(System.in);
        int []a=new int [5];
         for(int i=0;i<a.length;i++){
             a[i]= input.nextInt();
        }
         mppx(a);
         for (int i = 0; i <a.length ; i++) {
             System.out.print(a[i]+" ");
        }
    }

}

2.编写一个方法，求整数n的阶乘，例如5的阶乘是1*2*3*4*5。 [必做题]

import java.util.Scanner;
public class zuoye {
    public static int jc(int x) {
        int sum=1;
       for (int i = 1; i <=x ; i++) {
          sum*=i;
       }
       return sum;
    }

   public static void main(String[] args){
        Scanner input=new Scanner(System.in);
       int n=input.nextInt();
       System.out.println(n+"的阶层为"+jc(n));
    }
}

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

import java.util.Scanner;
public class zuoye {
    public static void year(int year){
        if (year%4==0&&year%100!=0||year%400==0) {
           System.out.println("闰年");
     }
       else {
            System.out.println("平年");
      }
    }


    public static void main(String[] args) {
        Scanner input=new Scanner(System.in);
        year(input.nextInt());
    }
}

4.课堂没完成的menu菜单，实现幸运抽奖功能

import java.util.Random;
import java.util.Scanner;
public class zuoye {
    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");
        System.out.println("请选择");
        int i=input.nextInt();
        switch(i){
        case 1:
            login();
            break;
        case 2:
            reg();
            break;
        case 3:
            lucky();
        
        }
        
        
    }
    
    private static void lucky() {
        // 输入四位会员卡号，如果百位数等于随机数，幸运会员。否则不是。同时也要询问是否返回主菜单
        Scanner input=new Scanner(System.in);
        Random r=new Random();
        int luck=r.nextInt(10);
     System.out.println("输入四位数会员卡号");
       int id= input.nextInt();
        if (id/100%10==luck) {
           System.out.println("幸运会员是"+id+"号");
      }
       else {
           System.out.println("不是幸运会员");
      }
       returnMain();

    }

    public static void returnMain(){
        Scanner input=new Scanner(System.in);
        System.out.println("是否返回主菜单？");
        if(input.next().equalsIgnoreCase("Y"))
            mainMenu();
        else
            System.out.println("谢谢使用");
    }
    
    public static void reg() {
        // TODO Auto-generated method stub
        Scanner input=new Scanner(System.in);
        System.out.println("输入要注册的用户名");
        String uname=input.next();
        System.out.println("输入注册密码");
        String upwd=input.next();
        System.out.println("注册成功");
        returnMain();
        
        
    }


    public static void login(){
        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("ok");
        }else{
            System.out.println("fail");
        }
        returnMain();        
    }
    

    
    public static void main(String[] args) {
        mainMenu();

    }
}