第九周作业

1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

package Te.nn;

import java.util.Scanner;

public class T2 {
public static void main(String[]args){
	Scanner input=new Scanner(System.in);
	System.out.println("请输入五个数");
	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 - 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("排序后为:");
    for (int i = 0; i < a.length; i++) {
        System.out.println(a[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 Te.nn;

import java.util.Scanner;

//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]
public class T3 {
	 public static int jc(int a) {
	        int sum = 1;
	        for (int i = 1; i <= a ; i++) {
	            sum *= i;
	        }
	        System.out.println(+a+"的阶乘是");
	        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 Te.nn;

import java.util.Scanner;

public class T4 {
	public static void prn() {
		Scanner input = new Scanner(System.in);
		System.out.println("请输入年份");
		int year = input.nextInt();
		if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
			System.out.println("是闰年");
		} else {
			System.out.println("是平年");
		}
	}

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

　　

 

 

4.课堂没完成的menu菜单，实现幸运抽奖功能

 

package Te.nn;

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

public class T1 {
	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("请输入一个四位数");
		int a = input.nextInt();
		Random r = new Random();
		int b = r.nextInt(10);

		int bai = a % 1000 / 100;
		if (bai == b) {
			System.out.println("您是幸运会员");
		} else {
			System.out.println("您不是幸运会员");
			System.out.println("幸运数字是" + b);
		}

		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();

	}

}