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 homework9;

public class Text1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         int []x={1,5,2,3,7,8,6};
           mp(x);
            for (int i = 0; i < x.length; i++) {
                System.out.println(x[i]);
            }
        }
        public static void mp(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 c = a[j];
                        a[j] = a[j + 1];
                        a[j + 1] = c;
                    }
                }
            }

    }

}

 

 

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 homework9;

public class Text2 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int sum=getSum(5);
        System.out.println(sum);

    }

    private static int getSum(int n) {
        // TODO Auto-generated method stub
        if(n==1){
            return 1;
        }
        int x=getSum(n-1);
        return x*n;
    }

}

 

 

3编写一个方法，判断该年份是平年还是闰年。[必做题]

package homework9;

import java.util.Scanner;

public class Text3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        year();
    }

    private static void year() {
        // TODO Auto-generated method stub
        Scanner input=new Scanner(System.in);
        int year=input.nextInt();
        if(year/100==0||year%4==0&&year/100!=0){
            System.out.println("今年是闰年");
        }
        else{
            System.out.println("今年是平年");
        }
    }

}

 

 

4

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


public class Menu {
    
    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
        Random m=new Random();
        int a=m.nextInt(10);
         System.out.println("("+a+")");
            Scanner input=new Scanner(System.in);
            System.out.println("输入四位会员卡号"); 
            int kahao= input.nextInt();
            while (kahao>10000||kahao<1000) {
                System.out.println("输入错误,重新输入");
                kahao = input.nextInt();
                if (kahao<10000&&kahao>=1000) {
                    break;
                }
            }
            int bai=kahao%1000/100;
            if (bai == a) {
                System.out.println("是幸运会员");
            } 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 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();

    }
    

}

课堂没完成的menu菜单，实现幸运抽奖功能