第10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 java作业;
import java.util.Scanner;

public class Java1 {

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

 

 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 java作业;
import java.util.Scanner;

public class Java1 {

    /**
     * @param args
     */
    
        // TODO Auto-generated method stub
        
        public static int jc(int a){
            int sum=1;
            for(int i=1;i<=a;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 java作业;
import java.util.Scanner;

public class Java1 {

    /**
     * @param args
     */
    
        // TODO Auto-generated method stub
        
     private static void prn() {
           Scanner input = new Scanner(System.in);
           System.out.println("请输入年份");
           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) {
           prn();
       }
    }

 

 4.课堂没完成的menu菜单，实现幸运抽奖功能

package java作业;
import java.util.Scanner;
import java.util.Random;
public class Java1 {
    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);
            Random r=new Random();
            int luck=r.nextInt(10);
            System.out.println("输入四位数会员卡号");
            int id=input.nextInt();
            if (luck==id) {
                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 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();

    }
    

}