第十次作业

1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

package ggg;

public class gggg {

     public static void main(int x[] ) {
        // TODO Auto-generated method stub
          int a = 0;
            for (int i = x.length - 1; i > 0; i--) {
                for (int j = 0; j < i; j++) {
                    if (x[j] > x[i]) {
                        a = x[j];
                        x[j] = x[i];
                        x[i] = a;
                    }
     
                }
     
            }
     
        }
     
        public static void main(String[] args) {
            int x[] = { 6, 5, 9, 2, 4, 1, 49 };
            main(x);
            for (int i : x) {
                System.out.print(i + " ");
            }
        }
    
    }

 

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 ggg;

public class gggg {

     public static void main(String [] args ) {
        // TODO Auto-generated method stub
          int sum1=jc(5);
          int sum2=jc(6);
            System.out.println(sum1);
            System.out.println(sum2);
        }
        public static int jc(int n){
            int sum=1;
            for (int i =1; i <=n; i++) {
                sum*=i;
            }
            return sum;
        }
    }

 

 3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package ggg;

import java.util.Scanner;

public class gggg {

     public static void lq(){
        // TODO Auto-generated method stub
         System.out.println("请输入一个年份");
            bc();
        }
        public static void bc() {
            Scanner input=new Scanner(System.in);
            int a=input.nextInt();
            if(a%4==0||a%400==0&&a%100!=0)
                System.out.println("是闰年");
                else
                    System.out.println("不是闰年");
            }
            public static void main(String[] args){
                lq();
             
        }
    }

 

4.课堂没完成的menu菜单，实现幸运抽奖功能

 

package ggg;

import java.util.Scanner;
import java.util.Random;
public class gggg {

    
    
         
                  public static void mainMenu(){
                      Scanner input=new Scanner(System.in);
                      System.out.println("欢迎使用本系统");
                      System.out.println("1.登录");
                      System.out.println("2.注册");
                      System.out.println("3.幸运抽奖");
                      System.out.println("4.退出");
                      System.out.println("请选择");
                      int i=input.nextInt();
                      switch(i){
                      case 1:
                          login();
                          break;
                      case 2:
                          reg();
                          break;
                      case 3:
                          lucky();

                      }


                  }

                  private static void lucky() {
                      // 输入四位会员卡号，如果百位数等于随机数，幸运会员。否则不是。同时也要询问是否返回主菜单
                      Scanner input=new Scanner(System.in);
                      Random r=new Random();
                      int luck=r.nextInt(10);
                   System.out.println("输入四位数会员卡号");
                     int id= input.nextInt();
                      if (id/100%10==luck) {
                         System.out.println("幸运会员是"+id+"号");
                    }
                     else {
                         System.out.println("不是幸运会员");
                    }
                     returnMain();

                  }

                  public static void returnMain(){
                      Scanner input=new Scanner(System.in);
                      System.out.println("是否返回主菜单？");
                      if(input.next().equalsIgnoreCase("Y"))
                          mainMenu();
                      else
                          System.out.println("谢谢使用");
                  }

                  public static void reg() {
                      // TODO Auto-generated method stub
                      Scanner input=new Scanner(System.in);
                      System.out.println("输入要注册的用户名");
                      String uname=input.next();
                      System.out.println("输入注册密码");
                      String upwd=input.next();
                      System.out.println("注册成功");
                      returnMain();


                  }


                  public static void login(){
                      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("ok");
                      }else{
                          System.out.println("fail");
                      }
                      returnMain();
                  }



                  public static void main(String[] args) {
                      mainMenu();

                  }
              }