第十周上机作业

1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

package nj666;

import java.util.Scanner;

public class w9 {

     public static void xn() {
           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-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=0;i<a.length;i++){
               System.out.println(a[i]);
           }
        }
        public static void main(String[] args){
            xn();
      }
    }

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 nj666;

public class w9 {

    public static int jc(int j) {
        int sum = 1;
        for (int i = 1; i <= j; i++) {
            sum *= i;
        }
        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 nj666;

import java.util.Scanner;

public class w9 {

    public static void wxszd() {
        Scanner input = new Scanner(System.in);
        System.out.println("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) {
        wxszd();
      }
   }

4.课堂没完成的menu菜单，实现幸运抽奖功能

package nj666;

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

public class w9 {

    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:
            register();
            break;
        case 3:
            choujiang();

        }

    }

    public static void choujiang() {
     
        Scanner input = new Scanner(System.in);
        System.out.println("输入四位会员卡号");
        Random r = new Random();
        int s = r.nextInt(10);
        int num = input.nextInt();
        while (num < 1000 || num > 10000) {
            System.out.println("输入有误,重新输入");
            num = input.nextInt();
            if (num >= 1000 && num < 10000) {
                break;
            }
        }
        int bai = num % 1000 / 100;
        if (bai == s) {
            System.out.println("幸运会员");
        } else {
            System.out.println("不是幸运会员");
        }

        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 register() {
        // 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 pwd = 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 pwd = input.next();
        if (uname.equals("zs") && pwd.equals("123")) {
            System.out.println("成功");
        } else {
            System.out.println("失败");
        }
        returnMain();
    }

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