第十次上机作业

1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

 public static void main(String[] args) {
	 int a[] = { 5, 7, 0, 4, 9, 3 };
     shengxu(a);
     for (int i = 0; i < a.length; i++) {
         System.out.print(a[i]);
     }
 }

 public static void shengxu(int a[]) {

     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 b = a[j];
                 a[j] = a[j + 1];
                 a[j + 1] = b;
             }
         }
     }
 }
}

　　

 

 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 home1 {

	 public static void main(String[] args) {
		 int sum=c(5);
	        System.out.println(sum);
	    }
	    public static int c(int n){
	        int a=1;
	        for (int i =1; i <=n; i++) {
	            a*=i;
	        }
	        return a;
	    }
	}

　　

 

 3.编写一个方法，判断该年份是平年还是闰年。[必做题]

import java.util.Scanner;
public class home1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        a();
    }
    public static void a(){
        Scanner input=new Scanner(System.in);
        System.out.println("输入年");
        int a=input.nextInt();
        if(a%4==0&&a%100!=0||a%400==0){
            System.out.println(a+"是闰年");
        }else{
            System.out.println(a+"是平年");
        }
    }
}

　　

 

 

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 home1 {

	public static void cd() {
		  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 a= input.nextInt();
	        switch (a) {
	        case 1:
	            jr();
	            break;
	        case 2:
	            zc();
	            break;
	        case 3:
	            yh();

	        }

	    }

	    public static void yh() {
	        Scanner input = new Scanner(System.in);
	        System.out.println("输入一个四位数");
	        Random b = new Random();
	        int x = b.nextInt(10);
	        int c = input.nextInt();
	        while (c < 1000 || c > 10000) {
	            System.out.println("输入有误,重新输入");
	            c = input.nextInt();
	            if (c >= 1000 && c < 10000) {
	                break;
	            }
	        }
	        int bai = c % 1000 / 100;
	        if (bai == x) {
	            System.out.println("幸运会员");
	        } else {
	            System.out.println("不是幸运会员");
	        }

	        xyg();
	    }

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

	    public static void zc() {
	        // 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");
	        xyg();

	    }

	    public static void jr() {
	        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("wzy") && upwd.equals("250")) {
	            System.out.println("ok");
	        } else {
	            System.out.println("fail");
	        }
	        xyg();
	    }

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

	    }

	}