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

import java.util.Scanner;

public class Text {
    public static void PX(){
        Scanner input=new Scanner(System.in);
        int []a=new int[5];
        int b;
        System.out.println("请输入5个数");
        for (int i = 0; i < a.length; i++) {
            a[i]=input.nextInt();
        }
        for (int i = 0; i < a.length; i++) {
            for (int j = i+1; j < a.length; j++) {
                if (a[i]>a[j]) {
                    b=a[i];
                    a[i]=a[j];
                    a[j]=b;
                }
            }
        }
        for (int i = 0; i < a.length; i++) {
            System.out.print(a[i]);
        }
    }
    public static void main(String[] args){
        PX();
    }
}

 

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。

import java.util.Scanner;

public class Text {

    public static void cc() {

        System.out.println("请输入一个数");
        jc();
    }

    public static void jc() {
        int d = 1;
        Scanner input = new Scanner(System.in);
        int a = input.nextInt();
        for (int b = 1; b <= a; b++) {
            d = d * b;
        }
        System.out.println("这个数的阶乘为" + d);
    }

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

 

3.编写一个方法，判断该年份是平年还是闰年

import java.util.Scanner;

public class Text {
    public static void cc() {

        System.out.println("请输入一个年份");
        pd();
    }

    public static void pd() {

        Scanner input = new Scanner(System.in);
        int a = input.nextInt();
        if (a % 4 == 0 || a % 400 == 0 && a % 100 != 0)
            System.out.println("是闰年");
        else
            System.out.println("不是闰年");

    }

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

 

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 Text {
    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();
            break;
        }
    }

    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 xdm = input.next();
        System.out.println("注册成功");
        returnMain();

    }

    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 xycj() {
        Scanner input = new Scanner(System.in);
        System.out.println("输入一个4位会员卡号");
        int number = input.nextInt();
        int c = number / 100 % 10;
        Random r = new Random();
        int a = (int) r.nextInt(10);
        if (c == a) {
            System.out.println("是幸运会员");
        } else {
            System.out.println("不是幸运会员");
        }
        returnMain();
    }

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

}