java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 exe2;

public class text {

        public static void px(int []a){
            for (int i = 0; i < a.length-1; i++) {
                for (int j = 0; j < a.length-1-i; j++) {
                    if(a[j]>a[j+1]){
                        int temp=a[j];
                        a[j]=a[j+1];
                        a[j+1]=temp;
                    }
                }
            }
        }
    public static void main(String[] args) {
        int []x={1,9,6,7,3,2};
        px(x);
        for (int i = 0; i < x.length; i++) {
            System.out.print(x[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 exe2;
public class text2 {

     public static int jc(int n){
         int sum=1;
         for (int a = 1; a <=n; a++) {
             sum*=a;
              
         }
         return sum;
     }
 public static void main(String[] args) {
     System.out.println(jc(5));

 }

}

 

 

 3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package exe2;

import java.util.Scanner;

public class text3 {

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

            }

        }

 

 4.课堂没完成的menu菜单，实现幸运抽奖功能

package exe2;

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

public class text4 {

     Scanner input=new Scanner(System.in);
     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):
                 luckly();
             break;
              
         }
     }
     public static void returnMenu(){
         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");
         }
     }
     private 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("wck")&&upwd.equals("1919")) {
             System.out.println("ok");
         }else{
             System.out.println("fail");
         }
         returnMenu();
     }
      
     private static void reg(){
         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("再次输入密码");
         String uppwd=input.next();
         if(upwd.equals(input())==uppwd.equals(input())){
             System.out.println("注册成功");
             System.out.println("用户名"+uname+"密码"+upwd);
         }else{
             System.out.println("密码错误");
         }
         returnMenu();
     }
      
     private static Object input() {
         // TODO Auto-generated method stub
         return null;
     }
     private static void luckly(){
         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 (luck==id) {
             System.out.println("幸运会员");
         }else{
             System.out.println("不是幸运会员");
         }
         returnMenu();
     }
     public static void main(String[] args) {
     mainMenu();

 }

}