第八次作业

1:完善menu注册功能,抽奖,看小故事等功能
package ty;

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

public class tt { 
    public static void main(String[] args) {
         // TODO Auto-generated method stub
         mainMenu();
    }
    public static void mainMenu() {
        Scanner input = new Scanner(System.in);
        System.out.println("欢迎使用本系统！！！！！！");
        System.out.println("1.登入");
        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:
            register();
            break;
        case 3:
            luck();
            break;
        case 4:
            lookstory();
            break;
        case 5:
            off();
            break;
        default:
            break;
        }
    }
    
    
    private static void login() {
        Scanner input = new Scanner(System.in);
        System.out.println("输入用户名：");
        String youName = input.next();
        System.out.println("输入密码：");
        String password = input.next();
        if (youName.equals("nmz") && password.equals("3344")) {
            System.out.println("登录成功");
        }else {
            System.out.println("登录失败");
        }
        returnMain();
    }
    
    
    private static void register() {
        Scanner input = new Scanner(System.in);
        System.out.println("输入昵称：");
        String jName = input.next();
        System.out.println("输入密码：");
        String password = input.next();
        System.out.println("注册成功");
        returnMain();
    }
    
    
    private static void luck() {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入四位会员卡号：");
        int hy = input.nextInt();
        Random sj = new Random();
        int x = sj.nextInt(10);
        if (hy/100%10 == x) {
            System.out.println("恭喜您中奖了");
        }else {
            System.out.println("谢谢参与");
        }
        returnMain();
    }
    
    private static void lookstory() {
        Scanner input = new Scanner(System.in);
        System.out.println("请选择想看的故事");
        System.out.println("1.三体");
        System.out.println("2.天才在左，疯子在右");
        System.out.println("3.苏菲的世界");
        int s = input.nextInt();
        switch (s) {
        case 1:
            System.out.println("1");
            break;
        case 2:
            System.out.println("2");
            break;
        case 3:
            System.out.println("3");
            break;
        default:
            break;
        }
        returnMain();
    }
    
    public static void off() {
        System.out.println("成功退出系统");
    }
    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");
        }
    }
}

　　

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。
package fr;

import java.util.*;

public class dde {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a = 1;
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入一个数:");
        int x = sc.nextInt();
        for (int i = 1; i <= x; i++) {
            a *= i;
        }
        System.out.println(x + "的阶乘为：" + a);
    }
}

　　

 3.编写一个方法，判断该年份是平年还是闰年。[必做题]
package xd;

import java.util.Scanner;

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

}