OOP Labs 7 Shapes

#include <iostream>
#include <cmath>

using namespace std;

class Shape{
    protected:
        int strana;
    public:
        Shape(){
            this->strana = 0;
        }
        Shape(const int a){
            this->strana = a;
        }
        ~Shape(){}
        virtual const double plostina() = 0;
        virtual const void pecati() = 0;
        virtual const int getType() = 0;
};

class Square : public Shape{
    public:
        Square(){}
        Square(const int a) : Shape(a){}
        ~Square();
        const double plostina(){
            return this->strana * this->strana;
        }
        const void pecati(){
            cout << "Kvadrat so plostina = " << this->plostina() << endl;
        }
        const int getType(){
            return 1;
        }
};

class Circle : public Shape{
    public:
        Circle(){}
        Circle(const int a) : Shape(a){}
        ~Circle();
        const double plostina(){
            return 3.14 * this->strana * this->strana;
        }
        const void pecati(){
            cout << "Krug so plostina = " << this->plostina() << endl;
        }
        const int getType(){
            return 2;
        }
};

class Triangle : public Shape{
    public:
        Triangle(){}
        Triangle(const int a) : Shape(a){}
        ~Triangle();
        const double plostina(){
            return (sqrt(3)/4) * this->strana * this->strana;
        }
        const void pecati(){
            cout << "Triagolnik so plostina = " << this->plostina() << endl;
        }
        const int getType(){
            return 3;
        }
};

void checkNumTypes(Shape ** niza, int n){
    int squares = 0; int circles = 0; int triangles = 0;
    for(int i=0; i<n; i++){
        if(niza[i]->getType() == 1)
            squares++;
        else if(niza[i]->getType() == 2)
            circles++;
        else if(niza[i]->getType() == 3)
            triangles++;
    }
    cout << "Broj na kvadrati vo nizata = " << squares << endl;
    cout << "Broj na krugovi vo nizata = " << circles << endl;
    cout << "Broj na triagolnici vo nizata = " << triangles << endl;
}
int main(){


    int n;
    cin >> n;

    Shape ** niza = new Shape* [n];

    int classType;
    int side;

    for(int i = 0; i < n; ++i){
        cin >> classType;
        cin >> side;
        if(classType == 1)
            niza[i] = new Square(side);
        else if(classType == 2)
            niza[i] = new Circle(side);
        else if(classType == 3)
            niza[i] = new Triangle(side);
    }


    for(int i = 0; i < n; ++i){

        niza[i]->pecati();
    }

    checkNumTypes(niza, n);


    return 0;
}