第八周java作业

package fff;

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。");
        System.out.println("4.看小故事。");
        System.out.println("5.退出程序。");
        System.out.println("请选择");
        int a = input.nextInt();
        switch(a){
        case 1: login(); 
        break; 
        case 2: zhuce(); 
        break; 
        case 3: huiyuan();
         break;
         case 4: look(); 
        break;
         case 5: esc();
        break;
        default:
            System.out.println("输入有误请重新输入:");
            mainMenu();
        }
    }
    public static void zhuce() { 
        System.out.println("请输入用户名:"); 
        Scanner input = new Scanner(System.in); 
        input.nextLine(); 
        System.out.println("请输入密码:"); 
        input.nextLine();
         System.out.println("注册完成"); 
        returnMain(); 
        } 
    public static void huiyuan() { 
        System.out.println("请输入四位会员卡号"); 
        Random sj = new Random(0 - 9); 
        Scanner input = new Scanner(System.in); 
        int x = input.nextInt(); 
        int y = sj.nextInt(); 
        int z = (x % 100) / 10; 
        if (z == y) { 
            System.out.println("恭喜您成为幸运会员"); 
            } else { 
                System.out.println("很抱歉您不是幸运会员"); 
                } 
        returnMain(); 
        } 
    public static void login() {
        // TODO Auto-generated method stub 
        Scanner input = new Scanner(System.in); 
        System.out.println("请输入用户名："); 
        String uname = input.next(); 
        System.out.println("请输入密码："); 
        String upwd = input.next(); 
        if (uname.equals("y") && upwd.equals("246")) { 
            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("谢谢您的使用"); 
            } 
        } 
    public static void look() { 
        System.out.println("请输入您想要看的故事名称"); 
        Scanner input = new Scanner(System.in); 
        input.next(); 
        System.out.println("感谢您的观看"); 
        returnMain(); 
        } 
    public static void esc() { 
        System.out.println("谢谢您的使用"); 
    }
}

import java.util.Scanner;
public class fff {
    public static void main(String[] args){
    int jc=1;
    Scanner sc = new Scanner(System.in);
    System.out.println("请输入一个整数");
    int x=sc.nextInt();
    for(int i=1;i<=x;i++){
        jc*=i;
    }
    System.out.println(x+"的阶乘："+jc);
    }
}

import java.util.Scanner;
public class fff {
    public static void main(String[] args){
    int year;
    Scanner sc = new Scanner(System.in);
    System.out.println(" 输入年份：");
     year= sc.nextInt();
     if(year%4==0&&year%100!=0||year%400==0){
         System.out.println(year+"年是闰年");
     }else{
         System.out.println(year+"年是平年");
     }
    }
}