第九次java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

 1 public void sor(int a[]){
 2         int mid=0;
 3         for (int i = 0; i < a.length; i++) {
 4             for (int j = 0; j < a.length-1; j++) {
 5                 if(a[j]>a[j+1]) {
 6                 mid=a[j];
 7                 a[j]=a[j+1];
 8                 a[j+1]=mid;
 9                 }
10             }
11         }
12         System.out.println("\n排序成功");
13     }

package text;

public class Run_001 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a[]=new int[] {10,20,90,45,83,34,49,76,66,54};
        System.out.println("排序前");
        for (int i : a) {
            System.out.print(i+" ");
        }
        work10 A=new work10();
        A.sor(a);
        for (int i : a) {
            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]

import java.util.Scanner;
public class zxcz {
    
    public static int jc(int a){
        int sum=1;
        for(int i=1;i<=a;i++){
            sum*=i;
        }
        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 test;

public class test3 {
    

        public static void main(String[] args) {
            test3 p = new test3();
                p.method(2000);
            }
            public void method(int year) {
                int a;
                a=year;
                if(a%4==0 && a%100!=0 || a%400==0) {
                    System.out.println(a+"是闰年");
                }else {
                    System.out.println(a+"不是闰年");
                }

        }

    }

4.课堂没完成的menu菜单，实现幸运抽奖功能

package boke5月7日;

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

public class Menu {

    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);
        System.out.println("输入四位会员卡号");
        int card = input.nextInt();
        Random r = new Random();
        int a = r.nextInt();
        if (card / 100 % 10 == a) {
            System.out.println("幸运会员");
        } else {
            System.out.println("不是幸运会员");
        }
        System.out.println("是否返回主菜单？");
    }

    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(uname);
        System.out.println("输入注册密码");
        String upwd = input.next();
        System.out.println(upwd);
        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();

    }

}