Абстрактные базовые классы

#include <iostream>
#include <cmath>
#include <string>
#include <fstream>
#include <ostream>
#include <sstream>
 
using namespace std;
 
class Figure {
public:
    
    virtual double Area() const = 0;
    virtual ~Figure() {}
};
 
 
 
class Piramida : public Figure {
    double x, y, h;
public:
 
    Piramida() : x(0), y(0), h(0) {}
    Piramida(double x1, double y1, double h1) : x(x1), y(y1), h(h1) {}
    virtual double Area() const {
        return x * y * h;
    }
};
 
class Sphere : public Figure {
    double r;
public:
    const double pi = 3.14;
    Sphere() : r(0) {}
    Sphere(double r1) : r(r1) {}
    virtual double Area() const {
        return (4 * pi*(pow(r, 3))) / 3;
    }
};
 
 
int main() {
    
    Figure * mas[2];
    mas[1] = new Piramida(5, 4, 3);
    mas[2] = new Sphere(3);
    cout << "Piramida" << endl << "Sphere" << endl;
    for (int i = 0; i < 3; i++) { 
        cout << "V= " << i + 1 << " = " <<  mas[i]->Area() << endl;
    }
 
    for (int i = 0; i != 4; ++i) {
        delete mas[i];
    }
 
    system("pause");
}

    mas[0] = new Piramida(5, 4, 3);
    mas[1] = new Sphere(3);