第八周作业

1:完善menu注册功能,抽奖,看小故事等功能

package demo01;
import java.util.*;
public class demo001 {
    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("***************************");
              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:
                  story();
                  break;
              case 5:
                  returnmain();
                  break;
              }
          }
          public static void login() {
              Scanner input = new Scanner(System.in);
              System.out.println("输入用户姓名");
              String uname=input.next();
              System.out.println("输入密码");
              String upwd=input.next();
              if(uname.equals("zs")&& upwd.equals("12321")){
                  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("注册姓名");
              String zname=input.next();
              System.out.println("注册密码");
              String zpwd=input.next();
              System.out.println("注册成功！");
              returnmain();
          }
          public static void choujiang(){
              Random r=new Random ();
              Scanner input=new Scanner(System.in);
              System.out.println("请输入四位会员号");
              int huiyuan=input.nextInt();
              int bai=huiyuan/100%10;
              int lucky=r.nextInt(10);
              if(bai==lucky){
                  System.out.println("您是幸运会员");
              }else{
                  System.out.println("您不是幸运会员");
              }
              returnmain();
          }
          public static void story(){
              Scanner input =new Scanner(System.in);
              System.out.println("请选择小故事：1 2 3 4返回菜单");
              int i=input.nextInt();
              switch (i) {
              case 1:
                  gs1();
                  break;
              case 2:
                  gs2();
                  break;
              case 3:
                  gs3();
                  break;
              case 5:
                  returnmain();
              }
              returnmain();
          }
          public static void gs1(){
              System.out.println("故事1");
          }
          public static void gs2(){
              System.out.println("故事二");
          }
          public static void gs3(){
              System.out.println("故事三");
          }
          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 demo01;
import java.util.*;
public class demo001 {
    public static void main(String[] args) {
        int sum=1;
        Scanner jc = new Scanner(System.in);
        System.out.println("请输入一个整数：");
        int k = jc.nextInt();
        for (int i = 1; i <= k; i++) {
            sum=sum*i;
        }
        System.out.println(k+"的阶乘为："+sum);
    }
}

3.编写一个方法，判断该年份是平年还是闰年。

package demo01;
import java.util.*;
public class demo001 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入一个年份：");
        long year = input.nextLong();
        if((year%4==0 && year%100!=0) || year%400==0 ){
            System.out.println(year+"年是闰年！");
        }else{
            System.out.println(year+"年不是闰年！");
        }
    }
}