JAVA第九次作业

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 work59 {
    public static void zs(){
        
        System.out.println("请输入几个数");
        xh();
        
    
        
    }

    public static void xh(){
        int d=0;
        Scanner input=new Scanner(System.in);
        int []b=new int[10];
        for(int a=0;a<10;a++){
            int c=input.nextInt();
            b[a]=c;
            for(int e=0;e<=a;e++){
                if(b[a]<b[e])
                {
                    d=b[a];
                    b[a]=b[e];
                    b[e]=d;
                }
            }
            }
        System.out.println("排序后");
        for (int i : b) {
            System.out.print(i);
        }
        
    }
    public static void main(String[] args) {
        zs();
    }
    
}

 

 

 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]

package nj666;

public class w9 {

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

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

 

 

 3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package work;

import java.util.Scanner;

public class test {
    public static void main(String[] args) {
     yp();
    }

    public static void yp() {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入年份");
        int year = input.nextInt();
        if (year % 4 == 0 && year % 100 != 100 || year % 400 == 0) {
            System.out.println("该年份为闰年");
        } else {
            System.out.println("该年份为平年");
        }
    }
}

 

 

 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();
    }
}