第十周作业

1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

package aaa;

public class Paixu {
    static int a[]= {1,6,2,9,3};
    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 b=a[j];
                    a[j]=a[j+1];
                    a[j+1]=b;
            
        }
        }
        }
    }
    public static void main(String[] args) {
        maopao(a);
        for (int i:a) {
            System.out.println(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 aaa;
import java.util.Scanner;
public class Jc {
    public static int jiechen(int n) {
        int sum=1;
        for(;n>0;n--) {
            sum*=n;
        }
        return sum;
    }
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("输入一个数");
        System.out.println("此数的阶乘为"+jiechen(input.nextInt()));
    }
}

import java.util.Scanner;
public class Jc {
    public static void jiechen(int n) {
        int sum=1;
        for(;n>0;n--) {
            sum*=n;
        }
        System.out.println("此数的阶乘为"+sum);
    }
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("输入一个数");
        jiechen(input.nextInt());
    }
}

 

 

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package aaa;
import java.util.Scanner;
public class Disanti {
    public static void panduan(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("输入一个年份");
        panduan(input.nextInt());
    }
}

 

 

4.课堂没完成的menu菜单，实现幸运抽奖功能

package aaa;
    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();

            }

        }

        public 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("输入一个四位数");
            Random r = new Random();
            int x = r.nextInt(10);
            int num = input.nextInt();
            while (num < 1000 || num > 10000) {
                System.out.println("输入有误,重新输入");
                num = input.nextInt();
                if (num >= 1000 && num < 10000) {
                    break;
                }
            }
            int bai = num % 1000 / 100;
            if (bai == x) {
                System.out.println("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();

        }

}