Статическая переменная класса vector

vector <string> Animals::animals;

#include <iostream>
#include <string>
#include <vector>
using namespace std;
 
void foo();
class Animals {
    string AnimalType;
    int price;
    string what;
    static vector <string> animals;
public:
    Animals(string AnimalType, int price)
    {
        this->price = price;
        this->AnimalType = AnimalType;
    }
    void ShowAnimals()
    {
        cout << "you purchased: " << AnimalType;
        animals.push_back(AnimalType);
        cout << "\nyour animals: \n";
        for (vector<string>::iterator it = animals.begin(); it < animals.end(); it++)
            it == animals.end() - 1 ? cout << *it << endl : cout << *it << ", ";
        foo();
    }
    
};
vector <string> Animals::animals;
 
void foo()
{
    Animals monkey("monkey", 500);
    Animals bear("bear", 300);
 
    int digit;
    cout << "what do you want to buy?\n1 - monkey, price: 500\n2 - bear, price:300" << endl;
    cin >> digit;
    digit == 1 ? monkey.ShowAnimals() : bear.ShowAnimals();
 
}
int main()
{
    foo();
    system("pause");
}