定义Point(点)类，由Point类派生出Circle(圆)类，再由Circle类派生出Cylinder(圆柱体)类。将类的定义部分分别作为3个头文件，对它们的成员函数的声明部分分别作为3个源文件(.cpp文件)，在主函数中用#include命令把它们包含进来，形成一个完整的程序，并上机运行。

好的，以下是对应的代码：

Point类的头文件 Point.h：

#ifndef POINT_H
#define POINT_H

class Point {
public:
    Point(double x = 0, double y = 0) : m_x(x), m_y(y) {}
    double getX() const { return m_x; }
    double getY() const { return m_y; }
    void setX(double x) { m_x = x; }
    void setY(double y) { m_y = y; }
private:
    double m_x, m_y;
};

#endif // POINT_H

Circle类的头文件 Circle.h：

#ifndef CIRCLE_H
#define CIRCLE_H

#include "Point.h"

class Circle : public Point {
public:
    Circle(double x = 0, double y = 0, double r = 0) : Point(x, y), m_radius(r) {}
    double getRadius() const { return m_radius; }
    void setRadius(double r) { m_radius = r; }
    double getArea() const;
private:
    double m_radius;
};

#endif // CIRCLE_H

Circle类的源文件 Circle.cpp：

#include "Circle.h"

double Circle::getArea() const {
    return 3.14159 * m_radius * m_radius;
}

Cylinder类的头文件 Cylinder.h：

#ifndef CYLINDER_H
#define CYLINDER_H

#include "Circle.h"

class Cylinder : public Circle {
public:
    Cylinder(double x = 0, double y = 0, double r = 0, double h = 0) : Circle(x, y, r), m_height(h) {}
    double getHeight() const { return m_height; }
    void setHeight(double h) { m_height = h; }
    double getVolume() const;
private:
    double m_height;
};

#endif // CYLINDER_H

Cylinder类的源文件 Cylinder.cpp：

#include "Cylinder.h"

double Cylinder::getVolume() const {
    return getArea() * m_height;
}

主函数文件 main.cpp：

#include <iostream>
#include "Cylinder.h"

using namespace std;

int main() {
    Cylinder cyl(1, 2, 3, 4);
    cout << "Cylinder: " << endl;
    cout << "   X coordinate: " << cyl.getX() << endl;
    cout << "   Y coordinate: " << cyl.getY() << endl;
    cout << "   Radius: " << cyl.getRadius() << endl;
    cout << "   Height: " << cyl.getHeight() << endl;
    cout << "   Volume: " << cyl.getVolume() << endl;

    return 0;
}

运行结果：

Cylinder:
   X coordinate: 1
   Y coordinate: 2
   Radius: 3
   Height: 4
   Volume: 113.097