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 oop;
public class t1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         int []a={200,98,300,98};
            mp(a);
            for (int i = 0; i < a.length; i++) {
                System.out.println(a[i]);
            }
    }
        public static void mp(int[]b){
            for (int i = 0; i < b.length - 1; i++) {
                for (int j = 0; j < b.length - 1 - i; j++) {
                    if (b[j] > b[j + 1]) {
                        int temp = b[j];
                        b[j] = b[j + 1];
                        b[j + 1] = temp;
                    }
                }
            }
        }
    
}

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 oop;

public class t2 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int sum=jc(5);
        System.out.println(sum);
    }
    public static int jc(int x){
        int sum=1;
        for (int i =1; i <=x; i++) {
            sum*=i;
        }
        return sum;
        

    }

}

 

 

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package oop;

import java.util.Scanner;

public class t3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        year();
    }
    public static void year(){
        Scanner input=new Scanner(System.in);
        System.out.println("请输入年份");
        int year=input.nextInt();
        if(year%4==0&&year%10!=0||year%400==0){
            System.out.println("是闰年");
        }else{
            System.out.println("是平年");
        }
        
    }

}

4.课堂没完成的menu菜单，实现幸运抽奖功能

package oop;

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

public class t4 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        mainMenu();
    }
        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("请输入四位会员卡号");
            Random r=new Random();
            int x=r.nextInt(100);
            int a=input.nextInt();
            while(a<1000||a>10000){
                System.out.println("请重新输入");
                a=input.nextInt();
                if(a<1000||a>10000){
                    break;
                }    
            }
            int bw=a%1000/100;
            if(bw==x){
                System.out.println("恭喜成为幸运会员");
             }else{
                System.out.println("很遗憾不是幸运会员");
            }
            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();        
        }
        
    
    }