Kvadrat i pravoagolnik - nasleduvanje

#include <iostream>
#include <cstring>

using namespace std;

class Kvadrat{
protected:
    double a;
public:
    // default constructor
    Kvadrat () { a = 0; }
    // constructor so argument
    Kvadrat ( double a ) {
        this -> a = a;
    }
    // copy constructor
    Kvadrat ( const Kvadrat &k ) {
        a = k.a;
    }
    // operator =
    Kvadrat & operator=( const Kvadrat &k ) {
        if(this!=&k){
            a = k.a;
        }
        return *this;
    }
    // metod perimetar
    double perimetar () { return 4*a; }
    // metod plostina
    double plostina () { return a*a; }
    // metod pecati
    void pecati () {
        cout<<"Kvadrat so dolzina a="<<a<<" ima plostina P="<<plostina()<<" i perimetar L="<<perimetar()<<endl;
    }
    // destructor
    ~Kvadrat () {}
};

class Pravoagolnik : public Kvadrat {
private:
    double x;
    double y;
public:
    // default constructor
    Pravoagolnik () : Kvadrat () { x=0; y=0; }
    // constructor so argumenti
    Pravoagolnik ( double a, double x, double y ) : Kvadrat ( a ) {
        this -> x = x;
        this -> y = y;
    }
    // copy constructor
    Pravoagolnik ( const Pravoagolnik &p ) {
        this -> a = p.a;
        this -> x = p.x;
        this -> y = p.y;
    }
    // constructor so argument kvadrat
    Pravoagolnik ( const Kvadrat &k, double x, double y ) : Kvadrat ( k ) {
        this -> x = x;
        this -> y = y;
    }
    // destructor
    ~Pravoagolnik () {}
    // operator =
    Pravoagolnik & operator=( const Pravoagolnik &p ) {
        if(this!=&p){
            this -> a = p.a;
            this -> x = p.x;
            this -> y = p.y;
        }
        return *this;
    }
    // prepokriena perimetar
    double perimetar () {
        return ( Kvadrat::perimetar() + 2*x + 2*y );
    }
    // prepokriena plostina
    double plostina () {
        return (a+x)*(a+y);
    }
    // prepokriena pecati
    void pecati () {
        if ( x == y ) {
            a+=x; x=0; y=0;
            Kvadrat :: pecati();
        }
        else{
                cout<<"Pravoagolnik so strani: "<<a+x<<" i "<<a+y<<" ima plostina P="<<plostina()<<" i perimetar L="<<perimetar()<<endl;
        }
    }

};


int main() {
    int n;
    double a,x,y;
    Kvadrat * kvadrati;
    Pravoagolnik * pravoagolnici;

    cin>>n;

    kvadrati = new Kvadrat [n];
    pravoagolnici = new Pravoagolnik [n];

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

        kvadrati[i] = Kvadrat(a);
    }

    for (int i=0;i<n;i++){
        cin>>x>>y;

        pravoagolnici[i]=Pravoagolnik(kvadrati[i],x,y);
    }

    int testCase;
    cin>>testCase;

    if (testCase==1){
        cout<<"===Testiranje na klasata Kvadrat==="<<endl;
        for (int i=0;i<n;i++)
            kvadrati[i].pecati();
    }
    else {
        cout<<"===Testiranje na klasata Pravoagolnik==="<<endl;
        for (int i=0;i<n;i++)
            pravoagolnici[i].pecati();
    }
}