Как перегрузить для полиморфного массива <

Недавно проходил перегрузку операторов. Сейчас задание написать полиморфный массив, но не знаю как перегрузить << для него. В классе Shop есть функция output, в которой записан цикл вывода. Думал достаточно буде перегрузить << для каждого класса, но к сожалению не так( Мне нужно либо для Shop перегрузить <<, чтобы вывести всю информацию массива, либо же создать метод output(как у меня), только рабочий.. Заранее спасибо)

P.s. Данные с файла file.txt

2

@ Pen China 20 1 1 2015

/#(без слеша) HeadPhones Italy 47 1 5 2016 technology

#include <iostream>
#include <fstream>
#include <string>
using namespace std;
ifstream filein("file.txt");
ofstream fileout("errors.txt");


class Product {
protected:
  string name, producer;
  float price;
  int day, month, year;
public:
  Product();
  Product(string n, string p, float pr, int d, int m, int y);
  Product(const Product& l);
  friend istream& operator>>(istream& in, Product& l);
  friend ostream& operator<<(ostream& out, Product& l);
};

Product::Product() :name(""), producer(""), price(0), day(0), month(0), year(0) {};
Product::Product(string n, string p, float pr, int d, int m, int y) {
  name = n;
  producer = p;
  price = pr;
  day = d;
  month = m;
  year = y;
}
Product::Product(const Product& l) {
  name = l.name;
  producer = l.producer;
  price = l.price;
  day = l.day;
  month = l.month;
  year = l.year;
}
istream& operator>>(istream& in, Product& l) {
in >> l.name >> l.producer >> l.price >> l.day >> l.month >> l.year;
if (l.price < 0) {
    fileout << "The price of " << l.name << " was less than zero. ";
    cout << "ERROR! Enter a new price of " << l.name << " : ";
    while (l.price < 0) {
        cin >> l.price;
    }
    fileout << "It was changed on - " << l.price << endl;
}
if (l.day < 0 || l.day > 31) {
    fileout << "The day of " << l.name << " was less than zero or bigger than thirty one. ";
    cout << "ERROR! Enter a new day of " << l.name << " : ";
    while (l.day < 0 || l.day > 31) {
        cin >> l.day;
    }
    fileout << "It was changed on - " << l.day << endl;
}
if (l.month < 0 || l.month > 12) {
    fileout << "The month of " << l.name << " was less than zero or bigger than twelve. ";
    cout << "ERROR! Enter a new month of " << l.name << " : ";
    while (l.month < 0 || l.month > 12) {
        cin >> l.month;
    }
    fileout << "It was changed on - " << l.month << endl;
}
if (l.year < 0 || l.year > 2020) {
    fileout << "The year of " << l.name << " was less than zero or bigger than two thousand and twenty. ";
    cout << "ERROR! Enter a new year of " << l.name << " : ";
    while (l.year < 0 || l.year > 2020) {
        cin >> l.year;
    }
    fileout << "It was changed on - " << l.year << endl;
}
  return in;
}
ostream& operator<<(ostream& out, Product& l) {
out << "Name - " << l.name << endl
    << "Producer - " << l.producer << endl
    << "Price - " << l.price << "$" << endl
    << "Date - " << l.day << "." << l.month << "." << l.year << endl << endl;
  return out;
}

class FarmProduct : public Product {
protected:
    string category;
public:
    FarmProduct();
    FarmProduct(string n, string p, float pr, int d, int m, int y, string c);

    friend istream& operator>>(istream& in, FarmProduct& l);
    friend ostream& operator<<(ostream& out, FarmProduct& l);

};

FarmProduct::FarmProduct() :category(""), Product() {}  
FarmProduct::FarmProduct(string n, string p, float pr, int d, int m, int y, string c) : Product(n, p, pr, d, m, y) {
  category = c;
}
istream& operator>>(istream& in, FarmProduct& l){
in >> l.name >> l.producer >> l.price >> l.day >> l.month >> l.year >> l.category;
if (l.price < 0) {
    fileout << "The price of " << l.name << " was less than zero. ";
    cout << "ERROR! Enter a new price of " << l.name << " : ";
    while (l.price < 0) {
        cin >> l.price;
    }
    fileout << "It was changed on - " << l.price << endl;
}
if (l.day < 0 || l.day > 31) {
    fileout << "The day of " << l.name << " was less than zero or bigger than thirty one. ";
    cout << "ERROR! Enter a new day of " << l.name << " : ";
    while (l.day < 0 || l.day > 31) {
        cin >> l.day;
    }
    fileout << "It was changed on - " << l.day << endl;
}
if (l.month < 0 || l.month > 12) {
    fileout << "The month of " << l.name << " was less than zero or bigger than twelve. ";
    cout << "ERROR! Enter a new month of " << l.name << " : ";
    while (l.month < 0 || l.month > 12) {
        cin >> l.month;
    }
    fileout << "It was changed on - " << l.month << endl;
}
if (l.year < 0 || l.year > 2020) {
    fileout << "The year of " << l.name << " was less than zero or bigger than two thousand and twenty. ";
    cout << "ERROR! Enter a new year of " << l.name << " : ";
    while (l.year < 0 || l.year > 2020) {
        cin >> l.year;
    }
    fileout << "It was changed on - " << l.year << endl;
}
  return in;
}
ostream& operator<<(ostream& out, FarmProduct& l) {
out << "Name - " << l.name << endl
    << "Producer - " << l.producer << endl
    << "Price - " << l.price << "$" << endl
    << "Date - " << l.day << "." << l.month << "." << l.year << endl
    << "Category - " << l.category << endl << endl;
  return out;
}

class Shop : public FarmProduct {
private:
  string Name;
  int size;
  Product** mas;
public:
  Shop();
  Shop(string n, int s);
  void input();
  void output();
};

Shop::Shop() : Name(""), size(0), FarmProduct() {}
Shop::Shop(string n, int s) : FarmProduct() {
Name = n;
size = s;
mas = new Product * [size];
}
void Shop::input() {
string symbol;
for (int i = 0; i < size; i++) {
    filein >> symbol;
    if (symbol == "@") {
        Product* pic = new Product;
        filein >> *pic;
        mas[i] = pic;
    }
    else if (symbol == "#") {
        FarmProduct* farm = new FarmProduct;
        filein >> *farm;
        mas[i] = farm;
    }
  }
}
void Shop::output() {
for (int i = 0; i < size; i++) {
    cout << mas[i];      // ошибка
} }

int Menu();

void Choice(string _name, int x, int n);

int main(){
  string _name;
  int n;
  filein >> n;
  cout << "Enter the name of your shop - ";
  getline(cin, _name);
  Choice(_name, Menu(), n);
}

int Menu() {
    cout << "1) Input info.\n"
    << "2) Find produce.\n"
    << "3) Find the cheapest product with some name.\n"
    << "4) Number of products with the same name.\n"
    << "5) Add or remove product.\n"
    << "6) Output info.\n\n"
    << "Your choice - ";
  int x;
  cin >> x;
  return x;
}

void Choice(string _name, int x, int n) {
Shop obj(_name, n);
switch (x)
{
case 1: {
    obj.input();
    Choice(_name, Menu(), n);
    break;
}
case 6: {
    obj.output();
    Choice(_name, Menu(), n);
}
default:
    break;
}
}