Как создать полиморфный массив?

#include <iostream>
#include <string>
#include <fstream>
using namespace std;
 
ifstream file("file.txt");
 
class Exhibit {
protected:
    string name;
    string author;
    int price;
    int year;
public:
    Exhibit() :name("none"), author("unknown"), price(0), year(0) {};
    Exhibit(string n, string a, int p, int _a) {
        name = n;
        author = a;
        price = p;
        year = _a;
    }
    Exhibit(const Exhibit& l) {
        name = l.name;
        author = l.author;
        price = l.price;
        year = l.year;
    }
};
 
class Sculpture : public Exhibit {
    string material;
public:
    Sculpture() :material("wood"), Exhibit() {}
    Sculpture(string n, string a, float p, short y, string m) :Exhibit(n, a, p, y) {
        material = m;
    }
    Sculpture(const Sculpture& l) :Exhibit(l) {
        material = l.material;
    }
    friend istream& operator>>(istream& in, Sculpture& l);
    friend ostream& operator<<(ostream& out, const Sculpture& l);
};
 
istream& operator>>(istream& in, Sculpture& l) {
    in >> l.name >> l.author >> l.price >> l.year >> l.material;
    return in;
}
ostream& operator<<(ostream& out, const Sculpture& l) {
    out << "Name: " << l.name << endl
        << "Author: " << l.author << endl
        << "Price: " << l.price << endl
        << "Year: " << l.year << endl
        << "Material: " << l.material << endl << endl;
    return out;
}
 
class Picture : public Exhibit {
    string genre;
public:
    Picture() :genre("classic"), Exhibit() {}
    Picture(string n, string a, float p, short y, string c) :Exhibit(n, a, p, y) {
        genre = c;
    }
    Picture(const Picture& l) :Exhibit(l) {
        genre = l.genre;
    }
    friend istream& operator>>(istream& in, Picture& l);
    friend ostream& operator<<(ostream& out, const Picture& l);
};
 
istream& operator>>(istream& in, Picture& l) {
    in >> l.name >> l.author >> l.price >> l.year >> l.genre;
    return in;
}
ostream& operator<<(ostream& out, const Picture& l) {
    out << "Name: " << l.name << endl
        << "Author: " << l.author << endl
        << "Price: " << l.price << endl
        << "Year: " << l.year << endl
        << "Genre: " << l.genre << endl << endl;
    return out;
}
 
int main() {
    try {               
        if (!file) {
            throw 1;
        }
    }
    catch(int a){
        cout << "Error " << a << " - File isn't opened.\n";
        system("pause");
        return 0;
    }
    string symbol = "";
    int size = 0;
    while (!file.eof()) {           
        file >> symbol;
        if(symbol == "#"){
            cout << "Picture\n";
            size++;
        }
        else if (symbol == "$") {
            cout << "Sculpture\n";
            size++;
        }
    }
    file.clear();
    file.seekg(0);
          // полиморфный массив
}