第八周课下作业

package mth;

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

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:
            zc();
            break;
        case 3:
            cj();
            break;
        case 4:
            storyn();
            break;
        case 5:
            tc();
            break;
        }
    }

    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 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");
        }

    }
    public static void zc(){
            Scanner input = new Scanner(System.in);
            System.out.println("======注册页面======");
            System.out.println("请输入用户名");
            String uname = input.next();
            System.out.println("输入密码");
            String upwd = input.next();
            System.out.println("======返回登录页面=====");
            login();
    }
    public static void storyn(){
        Scanner input = new Scanner(System.in);
        System.out.println("输入故事序号1，2，3，4，5");
        int i = input.nextInt();
        switch (i) {
        case 1:
            System.out.println("后羿射日");
            break;
        case 2:
            System.out.println("女娲补天");
            break;
        case 3:
            System.out.println("农夫与蛇");
            break;
        case 4:
            System.out.println("八仙过海");
            break;
        case 5:
            System.out.println("夸父逐日");
            break;
        }
        returnMain();
    }
    public static void cj(){
          Scanner input = new Scanner(System.in);
            Random r=new Random();
            int x=r.nextInt(10);
            System.out.println("随机数是"+x);
            System.out.println("请输入四位会员卡号");
            int u = input.nextInt();
            if(x==u/10%10) {
                System.out.println("是幸运会员!");
            }else {
                System.out.println("不是幸运会员");
            }
            returnMain();
    }
     private static void tc() {
            System.out.println("是否退出系统?Y/N");
            Scanner input = new Scanner(System.in);
            if (input.next().equalsIgnoreCase("Y")) {
                System.out.println("=====退出系统成功====");
            }else{
                mainMenu();
                
            }
        }

}

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 mth;

public class T1 {
        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.编写一个方法，判断该年份是平年还是闰年。[必做题]

package mth;

public class Ne {
    public static void main(String[] args) {
        near(2020);
    }
        public static void near(int y){
             if (y % 4 == 0 && y % 100 != 0 || y % 400 == 0) {
                    System.out.println(y + "年是闰年");
                } else {
                    System.out.println(y + "年不是闰年");
                }
        }

}