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

import java.util.Arrays;
import java.util.Random;

public class diyi {
    public static void main(String[] args) {
        
        int[] array= new int[5];
        
        Random random = new Random();
        
        for (int i = 0; i < array.length; i++) {
            array[i] = random.nextInt(100);
        }
        System.out.println("该随机数生成的数组："+Arrays.toString(array));
        

        bubble(array);
    }

    private static void bubble(int[] array) {
        for (int i = 0; i < array.length-1; i++) {
            for (int j = 0; j < array.length-1-i; j++) {
                if(array[j]>array[j+1]){
                    int temp =array[j];
                    array[j]=array[j+1];
                    array[j+1]=temp;
                }
            }
        }
        System.out.println(Arrays.toString(array));
        
        for (int i = 0; i < array.length; i++) {
            System.out.println(array[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]

public class jiechen {
    public static void main(String[] args) {
        int sum=getSum(7);
        System.out.println("阶乘="+sum);
         }
        
         public static int getSum(int num) {
          int result = 1;
          for(int i = 1;i<=num;i++){
           result *= i;
         }
          return result;
         }
        }

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

import java.util.Scanner;


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

4.课堂没完成的menu菜单，实现幸运抽奖功能

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


public class choujiang {
     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
            Random r=new Random();
            int a=r.nextInt(10);
            System.out.println("("+a+")");
            Scanner input=new Scanner(System.in);
            System.out.println("输入四位会员卡号"); 
            int kahao= input.nextInt();
            while (kahao < 1000 || kahao > 10000) {
                System.out.println("输入错误,重新输入");
                kahao = input.nextInt();
                if (kahao >= 1000 && kahao < 10000) {
                    break;
                }
            }
            int bai=kahao%1000/100;
            if (bai == a) {
                System.out.println("是幸运会员");
            } 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();

        }
        

    }