Java第九次作业

练习：

求平方和

package boke5月7日;

public class M1 {
    public static void square(double a, int b) {
        int sum = (int) (a * a + b * b);
        System.out.println("输出平方和");
        System.out.println(sum);

    }

    public static void main(String[] args) {
        square(1.5, 3);
    }
}

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 boke5月7日;

import java.util.Scanner;

public class Method {
    public static void Sort() {
        Scanner input = new Scanner(System.in);
        System.out.println("输入五个数");
        int[] a = new int[5];
        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 - i - 1; 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 i1 : a) {
            System.out.println(i1);
        }
    }

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

 

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 boke5月7日;

public class Method1 {
    public static int jc(int n) {
        int sum = 1;
        for (int i = 1; i <= n; i++) {
            sum *= i;
        }
        System.out.println("阶乘:");
        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 boke5月7日;

import java.util.Scanner;

public class Method2 {
    public static void nian() {
        Scanner input = new Scanner(System.in);
        System.out.println("输入一个年份");
        int year = input.nextInt();
        if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
            System.out.println("闰年");
        } else {
            System.out.println("平年");
        }
    }

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

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();

    }

}