Shape.h

#ifndef SHAPE_H
#define SHAPE_H


class Shape
{
    public:
        Shape();
        ~Shape();

        virtual double calcArea();

    protected:

    private:
};

#endif // SHAPE_H

Shape.cpp

#include "Shape.h"
#include<iostream>
using namespace std;

Shape::Shape()
{
    cout<<"Shape()"<<endl;
}

Shape::~Shape()
{
    cout<<"~Shape()"<<endl;
}

virtual double Shape::calcArea()
{
    cout<<"Shape::calcArea()"<<endl;
    return 0;
}

Circle.h

#ifndef CIRCLE_H
#define CIRCLE_H

#include "Shape.h"


class Circle : public Shape
{
    public:
        Circle(double r);
        ~Circle();

    protected:
        double m_dR;

    private:
};

#endif // CIRCLE_H

Circle.cpp

#include "Circle.h"
#include<iostream>
using namespace std;

Circle::Circle(double r)
{
    cout<<"Circle"<<endl;
    m_dR = r;
}

Circle::~Circle()
{
    cout<<"~Circle()"<<endl;
}

double Circle::calcArea()
{
    cout<<"Circle::calcArea()"<<endl;
    return 3.14*m_dR*m_dR;
}

Rect.h

#ifndef RECT_H
#define RECT_H

#include "Shape.h"


class Rect : public Shape
{
    public:
        Rect(double width,double height);
        ~Rect();

    protected:
        double m_dWidth;
        double m_dHeight;

    private:
};

#endif // RECT_H

Rect.cpp

#include "Rect.h"
#include<iostream>
using namespace std;

Rect::Rect(double width,double height)
{
    cout<<"Rect()"<<endl;
    m_dWidth = width;
    m_dHeight = height;
}

Rect::~Rect()
{
    cout<<"~Rect()"<<endl;
}

double Rect::calcArea()
{
    cout<<"Rect::calcArea()"<<endl;
    return m_dHeight*m_dWidth;
}

demo.cpp

#include<iostream>
using namespace std;
#include "Rect.h"
#include "Circle.h"


int main()
{
    Shape *shape1 = new Circle(4.3);
    Shape *shape2 = new Rect(2.0,3.0);

    shape1->calcArea();
    shape2->calcArea();

    delete shape1;
    shape1 = NULL;
    delete shape2;
    shape2 = NULL;

    system("pause");

    return 0;
}

error:

D:\code\C++\C++远征之多态\计算面积\src\Circle.cpp|16|error: no 'double Circle::calcArea()' member function declared in class 'Circle'|

求大神指导！！