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 bao;

public class Aa {
    // 1.编写一个方法，实现冒泡排序（由小到大），并调用该方法
        public static void maopao(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) {
    // TODO Auto-generated method stub
    int x[]={6,8,2,9,5,7,1,};
    maopao(x);
    for (int i = 0; i < x.length; i++) {
        System.out.println(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 bao;

public class Bb {

        // 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 static int jiecheng(int n){
            int sum=1;
            for (int i=n; i>0; i--) {
                sum=sum*i;
            }
            return sum;
        }
        public static void main(String[] args) {
            System.out.println(jiecheng(5));

        }

    }

 

 3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package bao;

import java.util.Scanner;

public class Cc {

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


    }

 

4.课堂没完成的menu菜单，实现幸运抽奖功能

 

 

package bao;

import java.util.Scanner;

public class Dd {
    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.退出系统");
        System.out.println("请选择：");
        int i = input.nextInt();
        switch (i) {
        case 1:
            login();
            break;
        case 2:
            register();
            break;
        case 3:
            xycj();
        }
    }

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

    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 pwd = input.next();
        if (uname.equals("admin") && pwd.equals("admin"))
            System.out.println("成功");
        else
            System.out.println("失败");
        returnMain();
    }

    public static void register() {
        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 pwd = input.next();
        System.out.println("注册成功");
        returnMain();
    }

    public static void xycj() {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入四位数卡号:");
        int kahao = input.nextInt();
        int random = (int) (Math.random() * 10);
        if (random == kahao / 100 % 10) {
            System.out.println("恭喜你是幸运会员!");
        } else {
            System.out.println("幸运数是:" + random);
            System.out.println("很遗憾你不是幸运会员!");
        }
        returnMain();
    }

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

}