C++头文件与CPP文件所包含的声明有什么区别，为什么这个小程序头文件出问题了

//Point.h

#ifndef Point.h
#define Point.h
class Point{
      double x,y;
      public:
             Point(double a=0,double b=0):x(a),y(b){}
             double yuandian()const;
             double liangdian(const Point& obj)const;
             int getx()const;
             int gety()const;
             void setxy(double a,double b);
             void move(double a,double b);
             };
#endif            
      
//Point.cpp


#include "Point.h"  
#include<math.h>
using namespace std;
             void Point::yuandian()const
             {
                  return sqrt(x*x+y*y);
             }
            
             void Point::liangdian(const Point& obj)const
             {
                  return sqrt(((x-obj.x)*(x-obj.x)+((y-obj.y)*(y-obj.y));
             }
            
             int Point::getx()const
             {
                 return x;
             }
             int Point::gety()const
             {
                 return y;
             }
             void Point::setxy(double a,double b)
             {
                  x=a;
                  y=b;
             }
            
             void Point::move(double a,double b)
             {
                  x=a;
                  y=b;
             }

//main

#include <cstdlib>
#include<math.h>
#include <iostream>
#include "Point.h"  
using namespace std;

int main(int argc, char *argv[])
{
   
    system("PAUSE");
    return EXIT_SUCCESS;
}

[ 本帖最后由 剑飘香 于 2011-12-10 23:15 编辑 ]