第八周作业

1.完善menu注册功能,抽奖,看小故事等功能

package haha;

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

public class hehe {

	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.退出系统");
		        System.out.println("请选择");
		        int i = input.nextInt();
		        switch (i) {
		        case 1:
		            login();
		            break;
		        case 2:
		            zhuce();
		            break;
		        case 3:
		        	reg();
		        	break;
		        case 4:
		        	text();
		        	break;
		        case 5:
		        	out();
		        	break;
		        }
		    }

		    public 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("用户名");
		        String uname = input.next();
		        System.out.println("密码");
		        String upwd = input.next();
		        if(uname.equals(null) || upwd.equals(null) ) {
		            System.out.println("注册失败");
		        }else {
		            System.out.println("注册成功");
		        }
		        returnmain();
		    }
		    public static void reg() {
		    	Scanner input = new Scanner(System.in);
		        System.out.println("请输入四位会员卡号");
		        int x = input.nextInt();
		        Random r = new Random();
		        int a = r.nextInt(10);
		        if (x / 10 % 10 == a) {
		            System.out.println("恭喜中奖");
		        } else {
		            System.out.println("谢谢参与");
		        }
		        returnmain();
		    }
		    public static void text() {
		    	Scanner input = new Scanner(System.in);
		    	System.out.println("请选择故事:");
		        System.out.println("1.大灰狼");
		        System.out.println("2.白雪公主");
		        int m = input.nextInt();
		        switch(m) {
		        case 1:
		            System.out.println("大灰狼");
		            break;
		        case 2:
		            System.out.println("白雪公主");
		            break;
		            }
		            returnmain();
		        }
		            
		    public static void out() {
		        System.out.println("是否退出系统Y/N");
		        Scanner input = new Scanner(System.in);
		        String a = input.next();
		        if(a.equalsIgnoreCase("y")) {
		            System.out.println("退出系统成功");
		        }else {
		            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.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 haha;

import java.util.Scanner;
public class hehe {
	
		   public static int jc(int a) {
		        int x = 1;
		        for (int i = 1; i <= a; i++) {
		            x *= i;
		        }
		        return x;
		    }
		   
		    public static void main(String[] args) {
		        System.out.println("请输入数字：");
		        Scanner input = new Scanner(System.in);
		        int i = input.nextInt();
		        System.out.println("阶乘是"+jc(i));
		    }
		} 

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package haha;

import java.util.Scanner;

public class hehe {
	 public static void nian(int year) {
		        if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
		            System.out.println("该年是闰年");
		        } else {
		            System.out.println("该年不是闰年");
		        }
		    }

		    public static void main(String[] args) {
		        Scanner input = new Scanner(System.in);
		        System.out.println("输入一个年份:");
		        int a = input.nextInt();
		        nian(a);
	        }
            }