Shapes lab OOP polimorfizam

#include <iostream>
#include <cmath>
using namespace std;
class Shape
{
    protected:
    int a;
    public:
    Shape(int a = 0)
    {
    this->a=a;
    }
    virtual double ploshtina ()=0;
    virtual void pecati()=0;
    virtual int getType()=0;
};
class Square :public Shape
{
    public:
    Square(int a = 0) :Shape(a){}


    double ploshtina()
    {
    return a*a;
    }

    void pecati()
    {
    cout<<"Kvadrat so plostina = "<<ploshtina()<<endl;
    }
    int getType()
    {
        return 1;
    }

};
class Circle :public Shape
{
    public:
    Circle(int a=0): Shape(a){}

    double ploshtina()
    {
    return 3.14*a *a;
    }
    void pecati()
    {
    cout<<"Krug so plostina = "<<ploshtina()<<endl;
    }
    int getType()
    {
    return 2;
    }


};
class Triangle:public Shape
{
    public:
    Triangle(int a=0) :Shape(a){}

    double ploshtina()
    {
    return (sqrt(3)/4) * a * a;
    }
    void pecati()
    {
    cout<<"Triagolnik so plostina = "<<ploshtina()<<endl;
    }
    int getType(){
    return 3;
    }
};
void checkNumTypes(Shape** niza, int n)
{
    int brojac=0 , brojac1=0, brojac2=0;
    for(int i = 0 ; i < n ; i ++ )
    {
    Square *s= dynamic_cast<Square*>(niza[i]);
        if(s!=0){
            brojac++;
    }
    Circle*c=dynamic_cast<Circle*>(niza[i]);
        if(c!=0)
        {
        brojac1++;
        }
   Triangle*t=dynamic_cast<Triangle*>(niza[i]);
        if(t!=0)
        {
        brojac2++;
        }
}
    cout<<"Broj na kvadrati vo nizata = "<<brojac<<endl;
    cout<<"Broj na krugovi vo nizata = "<<brojac1<<endl;
    cout<<"Broj na triagolnici vo nizata = "<<brojac2<<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;
}