第八周作业

1.

package test;

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

public class LH {

    
    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 :
            xiaogushi();
            break;
        case 5:
            System.out.println("退出");
            }
    }

    private 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("ltt") && 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);
        System.out.println("抽奖模式");
        Random r=new Random();
        int sjs=r.nextInt(10);
        System.out.println("请输入四位会员数");
        int num=input.nextInt();
        if(num/100%10==sjs) {
            System.out.println("恭喜你，是幸运会员");
        }else {
            System.out.println("祝你下次好运");
        }
        returnMain();
    }
    public static void xiaogushi() {
        System.out.println("吃菠萝包的方法");
        System.out.println("1.张嘴");
        System.out.println("2.咬下去");
        System.out.println("3.扔皮");
        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.

package test;
public class LH {
        public static int jc(int a){
            int sum=1;
            for (int i = 1; i <=a; i++) {
                sum*=a;
                 
                 
            }
            return sum;
        }
        public static void main(String[] args) {
            System.out.println(jc(6));
        }
}

3.

public class LH {
    public static void main(String[] args) {
        year(2020);
    }

    public static void year(int n){
        if (n%4==0&&n%100!=0||(n%400==0)){
            System.out.println(n+"是闰年");
        }else {
            System.out.println(n+"不是闰年");
        }
    }
}