本人新手菜鸟一个.恳请大家帮个忙，给看看这错是怎么回事。这一个算两点间距离的程序..先谢谢啦

Question

放在MYEclipse中能通过并运行。可视在DOS端中javac PointDemo总是报错说找不到符号
package Mypoint;
class Point
{
public int x;
public int y;

    public void Point(int a,int b)
    {
        this.x=a;
        this.y=b;
    }


    public void display()
    {
        System.out.println("您创建了一个X坐标为："+x+",Y坐标为："+y+"的点("+x+","+y+")");
        System.out.println("--------------------------------");
    }

}

import java.util.Scanner;
class PointDemo
{
public static void distance(Point a,Point b)
{
float m;
m=(float) Math.sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
System.out.println("这两个点之间的距离为："+m);
}
public static void main(String[] args)
{
System.out.println("本程序要实现的是计算两点之间的距离，点由用户来进行输入-----");
Scanner A=new Scanner(System.in);
Scanner B=new Scanner(System.in);
Scanner C=new Scanner(System.in);
Scanner D=new Scanner(System.in);

    System.out.println("请输入第1.个点:");
    int a,b;
    a=A.nextInt();
    b=B.nextInt();
    Point p1=new Point(a,b);
    p1.display();


    System.out.println("请输入第2.个点：");
    int c,d;
    c=C.nextInt();
    d=D.nextInt();
    Point p2=new Point(c,d);
    p2.display();


    distance(p1,p2);
}

}

Answer 1

PointDemo要放在单独的文件中，文件名是PointDemo.java，并且和主程序在一个路径下