java第八周课后作业

1.系统小练习

package homework;

import java.util.Random;
import java.util.Scanner;

public class Menu {

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

	public static void mainMenu() {
		Scanner input = new Scanner(System.in);
		System.out.println("****************");
		System.out.println("   1. 登录");
		System.out.println("   2. 注册");
		System.out.println("   3.幸运抽奖");
		System.out.println("   4.看小故事");
		System.out.println("   5.退出系统");
		System.out.println("****************");
		System.out.print("请选择:");
		int i = input.nextInt();
		switch (i) {
		case 1:
			login();
			break;
		case 2:
			register();
			break;
		case 3:
			luck();
			break;
		case 4:
			story();
			break;
		case 5:
			exit();
			break;
		default:
			System.out.println("该系统暂未开放其它功能！");
			break;
		}
	}

	private static void login() {
		// TODO Auto-generated method stub
		Scanner input = new Scanner(System.in);
		System.out.print("请输入您的用户名：");
		String uname = input.next();
		System.out.print("请输入您的密码：");
		String upwd = input.next();
		if (uname.equals("zs") && upwd.equals("123")) {
			System.out.println("登录成功!");
		} else {
			System.out.println("登录失败");
		}
		returnMain();

	}

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

	}

	public static void register() {
		Scanner input = new Scanner(System.in);
		System.out.print("请输入您的用户名:");
		String uname = input.next();
		System.out.print("请输入您的密码：");
		String upwd = input.next();
		System.out.println("您的账号已注册成功！！！");
		returnMain();
	}

	public static void luck() {
		System.out.println("**************************************欢迎来到幸运抽奖界面！*************************************");
		System.out.println(" *******规则为：如果您输入的四位会员卡号的百位等于系统随机数,您将成为我们的幸运会员,否则不是*******");
		Scanner input = new Scanner(System.in);
		int temp = 0;
		for (int i = 0;; i++) {
			System.out.print("请您输入四位的会员卡号：");
			int vipcard = input.nextInt();
			int bai = vipcard % 1000 / 100;
			temp = bai;
			if (vipcard < 999 || vipcard > 9999) {
				System.out.println("您的会员卡号错误,请您重新输入！");
			} else {
				break;
			}
		}
		Random r = new Random();
		int num = r.nextInt(9);
		System.out.println("系统生成的百位随机数为：" + num);
		if (num == temp) {
			System.out.println("恭喜您,成为我们的幸运会员！");
		} else {
			System.out.println("很遗憾,谢谢您的参与！");
		}
		returnMain();
	}

	public static void story() {
		System.out.println("欢迎您来到小故事界面,请您输入相应的数字(1-3)进行观看！");
		for (int i = 0;; i++) {
			Scanner input = new Scanner(System.in);
			int num = input.nextInt();
			switch (num) {
			case 1:
				System.out.println("男儿事业多，何必学读书 —— 宋 · 张耒《阿几》");
				break;
			case 2:
				System.out.println("阿爷无大儿，木兰无长兄，愿为市鞍马，从此替爷征 —— 南北朝 · 佚名《木兰诗 / 木兰辞》");
				break;
			case 3:
				System.out.println("大儿荷锸去疏麻，小儿提筐来采茶，翁自決水灌秧芽 —— 宋 · 艾性夫《田家词》");
				break;
			default:
				System.out.println("您的输入有错,请重新输入！");
			}
			break;
		}
		returnMain();
	}

	public static void exit() {
		System.out.println("是否退出该系统?Y/N");
		Scanner input = new Scanner(System.in);
		if (input.next().equalsIgnoreCase("N")) {
			mainMenu();
		} else {
			System.out.println("您已退出我们的系统,谢谢使用!");
		}

	}

}

2.编写一个方法，求整数n的阶乘 例如5的阶乘是5*4*3*2*1

	public static int Jc(int n) {
		int cj=1;
		for (int i = 1; i <= n; i++) {
			cj*=i;
		}
		return cj;
	}
	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

	public static void Year(int n) {
		if (n % 4 == 0 && n % 100 != 0 || n % 400 == 0) {
			System.out.println(n + "是闰年");
		} else {
			System.out.println(n + "是平年");
		}
	}

	public static void main(String[] args) {
		Year y = new Year();
		Year(2020);
	}