第十周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

package ktlx;

import java.util.Scanner;

public class MaoPaoPaiXu {
    public static void px() {
        Scanner input = new Scanner(System.in);
        int[] a = new int[5];
        System.out.println("输入五数");
        for (int i = 0; i < a.length; i++) {
            a[i] = input.nextInt();
        }
        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;
                }
            }
        }
        System.out.println("排序后:");
        for (int i : a) {
            System.out.println(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。 [必做题]

package ktlx;

import java.util.Scanner;

public class zy2 {
    public static int jc(int n) {
        int sum = 1;
        for (int i = 1; i <= n; i++) {
            sum *= i;
        }
        System.out.println(n+"的阶乘为");
        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 ktlx;

import java.util.Scanner;

public class zy3 {
    public static void year() {
        System.out.println("输入一个年份：");
        Scanner input = new Scanner(System.in);
        int a = input.nextInt();
        if (a % 4 == 0 && a % 100 != 0 || a % 400 == 0) {
            System.out.println("是闰年");
        } else {
            System.out.println("不是闰年");
        }

    }

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

}

4.课堂没完成的menu菜单，实现幸运抽奖功能

package ktlx;

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.退出系统");
        System.out.println("请选择：");
        int i = input.nextInt();
        switch (i) {
        case 1:
            login();
            break;
        case 2:
            register();
            break;
        case 3:
            luckdraw();
            break;
        case 4:
            secede();
            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 pwd = 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 luckdraw() {
        System.out.println("请在1~10中选择一个数");
        Scanner input = new Scanner(System.in);
        int a = input.nextInt();

        Random s = new Random();
        int b = s.nextInt(10) + 1;
        if (a == b) {
            System.out.println("恭喜你中奖了");
        } else {
            System.out.println("很遗憾,请再接再厉!");
        }
        returnMain();

    }

    public static void secede() {
        System.out.println("欢迎再次使用");
        returnMain();
    }

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

}