Java第九次作业

1.编写个方法,实现冒泡排序,并调用该方法(从小到大)

package bse;

public class j1 {

    /**
     * @param args
     */
    public static void mp(int a[]) {
        // TODO Auto-generated method stub

        for (int i = 0; i <= a.length; i++) {
            for (int j = 0; j < a.length-1-i; j++) {
                if(a[j]>a[j+1]){
                    int t=a[j];
                    a[j]=a[j+1];
                    a[j+1]=t;
                }
            }
        }
    }

    public static void main(String[] args) {
        int m[]={11,333,23,44,56,67,87,33};
        mp(m);
        for (int i= 0; i < m.length; i++) {
            System.out.println(m[i]);
        }
    }
}

2.编写一个方法,求整数n阶乘

package bse;

public class j2 {

    public static int jc(int n){
        // TODO Auto-generated method stub

        int sum=1;
        for (int i = 1; i <= n; i++) {
            sum*=i;
        }

    return sum;
   }
    public static void main(String[] args) {
        System.out.println(jc(5));
    }
}

3.编写一个方法,判断平闰年

package bse;

import java.util.Scanner;

public class j2 {

    public static void pr(int year){
        // TODO Auto-generated method stub

        if(year%4==0&&year%100!=0){
            System.out.println("是闰年");
        }else{
            System.out.println("是平年");
        }
   }
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        System.out.println("输入年份");
        pr(sc.nextInt());
    }
}

4.完成menu菜单

package bse;

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


public class j2 {
    
    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);
        System.out.println("请输入卡号");
        int bai=input.nextInt();
        Random a=new Random();
        int b=a.nextInt();
        if(bai%1000/100==b){
            System.out.println("是幸运会员");
        }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();
    }
}