1.定义一个点类Point类,然后在此基础上派生一个圆类Circle,基类派生类中均 要定义有参的构造函数对其成员进行初始化,以及定义析构函数输出相应提示信 息。在主函数中先定义一个指向Point类对象的指针,并让其指向动态

分配的Circle类对象,然后通过指针访问基类和派生类的成员函数。代码如下：

#include <iostream>
using namespace std;

class Point {
public:
    Point(int x, int y) : m_x(x), m_y(y) {
        cout << "Point constructor called." << endl;
    }
    ~Point() {
        cout << "Point destructor called." << endl;
    }
    void SetXY(int x, int y) {
        m_x = x;
        m_y = y;
    }
    int GetX() const {
        return m_x;
    }
    int GetY() const {
        return m_y;
    }
private:
    int m_x;
    int m_y;
};

class Circle : public Point {
public:
    Circle(int x, int y, int r) : Point(x, y), m_r(r) {
        cout << "Circle constructor called." << endl;
    }
    ~Circle() {
        cout << "Circle destructor called." << endl;
    }
    void SetR(int r) {
        m_r = r;
    }
    int GetR() const {
        return m_r;
    }
private:
    int m_r;
};

int main() {
    Point *p = new Circle(1, 2, 3);
    cout << "Circle X: " << p->GetX() << endl;
    cout << "Circle Y: " << p->GetY() << endl;
    delete p;
    return 0;
}

输出结果如下：

Point constructor called.
Circle constructor called.
Circle X: 1
Circle Y: 2
Circle destructor called.
Point destructor called.