第八周作业

1

package ffff;

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

public class Menu {

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

    public static void mainMenu() {
        Scanner input = new Scanner(System.in);
        System.out.println("1.登录");
        System.out.println("2.注册");
        System.out.println("3.幸运抽奖,输入四位会员卡号,如果百位等于系统随机数,就是星运会员.否则不是.");
        System.out.println("4.看小故事,");
        System.out.println("5.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:
            choujiang();
            break;
        case 4 :
            kanshu();
            break;
        case 5:
            System.out.println("退出");
            }
    }

    private 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("输入用户名");
        String uname = input.next();
        System.out.println("输入密码");
        String upwd = input.next();
        System.out.println("注册成功");
        returnMain();
    }
    public static void choujiang(){
        Scanner input = new Scanner(System.in);
        Random r= new Random();
        int a = input.nextInt();
        int b=r.nextInt(10);
        if(a/100%10==b){
            System.out.println("yes");
        }
        else{
            System.out.println("no");
        }
        returnMain();
        
    }
    public static void kanshu(){
        System.out.println("各种故事 ");
    
    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");
        }

    }
    

}

2 j阶乘

package ffff;
import java.util.*;
public class jdjd {
         public static int jc(int a){
            int sum=1;
            for (int i = 1; i <=a; i++) {
                sum*=i;
            }
             return sum;
         }
         public static void main(String[] args) {
            Scanner input=new Scanner(System.in);
            int i=input.nextInt();
            System.out.println("阶乘是"+jc(i));
        }
}

3

package ffff;
import java.util.*;
public class jdjd {
         public static void naian(int year){
             if(year%4==0&&year%100==0||year%400==0){
                 System.out.println("yes");
                 
             }
             else{
                 System.out.println("no");
             }
         
         }
         public static void main(String[] args) {
            Scanner input=new Scanner(System.in);
            System.out.println("输入年份");
            int i=input.nextInt();
            naian(i);
        }
}