Java第十次作业

1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

package test;
import java.util.Scanner;
public class t1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input=new Scanner(System.in);
        System.out.println("输入五个数");
        int[]a=new int[5];
        for(int x=0;x<5;x++){
            a[x]=input.nextInt();
        } 
        for(int x=0;x<4;x++){
            for (int y=0;y<4-x; y++){
                if (a[y]>a[y+1]){
                    int b=a[y];
                    a[y]=a[y+1];
                    a[y+1]=b;
                }
            }
        }
        System.out.println("排序后为:");
        for(int x=0;x<5; x++){
            System.out.println(a[x]);
        }

    }

}

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 test;
import java.util.Scanner;
public class t1 {
     public static int jc(int a) {
         int x=1;
         for(int y=1;y<=a;y++){
             x*=y;
         }
         System.out.println(a+"的阶乘是");
         return x;
     }

     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 test;
import java.util.Scanner;
public class t1 {
    private static void prn() {
           Scanner input = new Scanner(System.in);
           System.out.println("输入年份");
           int x=input.nextInt();
           if(x%4==0&&x%100!=0||x%400==0){
               System.out.println("闰年");
             }
           else{
             System.out.println("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 test;
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.注册");
            System.out.println("2.登录");
            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):
                    reg();
                break;
                case(2):
                    login();
                break;
                case(3):
                    luckly();
                break;
                 
            }
        }
        public static void returnMenu(){
            Scanner input=new Scanner(System.in);
            System.out.println("是否返回主菜单");
            if (input.next().equalsIgnoreCase("T")) {
                mainMenu();
            }else{
                System.out.println("谢谢使用");
            }
        }
        private 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("lh")&&upwd.equals("420")) {
                System.out.println("ok");
            }else{
                System.out.println("fail");
            }
            returnMenu();
        }
         
        private static void reg(){
            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("再次输入密码");
            String uppwd=input.next();
            if(upwd.equals(input())==uppwd.equals(input())){
                System.out.println("注册成功");
                System.out.println("用户名"+uname+"密码"+upwd);
            }else{
                System.out.println("密码错误");
            }
            returnMenu();
        }
         
        private static Object input() {
            // TODO Auto-generated method stub
            return null;
        }
        private static void luckly(){
            Scanner input=new Scanner(System.in);
            Random r=new Random();
            int lucky=r.nextInt(10);
            System.out.println("输入四位数会员卡号");
            int nb=input.nextInt();
            if (lucky==nb) {
                System.out.println("幸运会员");
            }else{
                System.out.println("不是幸运会员");
            }
            returnMenu();
        }
        public static void main(String[] args) {
        mainMenu();     
    }

}