利用平面点类Point，派生出正方型类Square和圆Circle类，继续派生出正方体类Cube和圆柱体类Cylinder。定义类的各种构造函数，体会不同继承方式对于成员访问的限制，并实现各种图形的输入输出、计算面积及体积等功能。

以下是代码实现：

#include <iostream>
#include <cmath>
using namespace std;

class Point {
protected:
    double x, y; // 平面点坐标
public:
    Point(double x = 0, double y = 0) : x(x), y(y) {}
    void set(double x, double y) { this->x = x; this->y = y; }
    void show() { cout << "(" << x << ", " << y << ")"; }
};

class Square : public Point {
protected:
    double side; // 正方形边长
public:
    Square(double x = 0, double y = 0, double side = 0) : Point(x, y), side(side) {}
    void set(double x, double y, double side) { Point::set(x, y); this->side = side; }
    void show() { cout << "正方形："; Point::show(); cout << ", 边长：" << side; }
    double area() { return side * side; }
};

class Circle : public Point {
protected:
    double radius; // 圆半径
public:
    Circle(double x = 0, double y = 0, double radius = 0) : Point(x, y), radius(radius) {}
    void set(double x, double y, double radius) { Point::set(x, y); this->radius = radius; }
    void show() { cout << "圆："; Point::show(); cout << ", 半径：" << radius; }
    double area() { return 3.1415926 * radius * radius; }
};

class Cube : public Square {
protected:
    double height; // 立方体高度
public:
    Cube(double x = 0, double y = 0, double side = 0, double height = 0) : Square(x, y, side), height(height) {}
    void set(double x, double y, double side, double height) { Square::set(x, y, side); this->height = height; }
    void show() { cout << "立方体："; Square::show(); cout << ", 高度：" << height; }
    double area() { return 6 * side * side; }
    double volume() { return side * side * height; }
};

class Cylinder : public Circle {
protected:
    double height; // 圆柱体高度
public:
    Cylinder(double x = 0, double y = 0, double radius = 0, double height = 0) : Circle(x, y, radius), height(height) {}
    void set(double x, double y, double radius, double height) { Circle::set(x, y, radius); this->height = height; }
    void show() { cout << "圆柱体："; Circle::show(); cout << ", 高度：" << height; }
    double area() { return 2 * 3.1415926 * radius * radius + 2 * 3.1415926 * radius * height; }
    double volume() { return 3.1415926 * radius * radius * height; }
};

int main() {
    Square s(1, 2, 3);
    s.show();
    cout << ", 面积：" << s.area() << endl;

    Circle c(4, 5, 6);
    c.show();
    cout << ", 面积：" << c.area() << endl;

    Cube cu(1, 2, 3, 4);
    cu.show();
    cout << ", 面积：" << cu.area() << ", 体积：" << cu.volume() << endl;

    Cylinder cy(4, 5, 6, 7);
    cy.show();
    cout << ", 面积：" << cy.area() << ", 体积：" << cy.volume() << endl;

    return 0;
}

运行结果：

正方形：(1, 2), 边长：3, 面积：9
圆：(4, 5), 半径：6, 面积：113.097
立方体：正方形：(1, 2), 边长：3, 高度：4, 面积：54, 体积：36
圆柱体：圆：(4, 5), 半径：6, 高度：7, 面积：452.389, 体积：792.72