C++ append into empy array

#include <iostream>
#include <cmath>
using namespace std;
void Shop(int);

int Gold = 10;

int HealthPotion = 0;
int ManaPotion = 0;

int Choice;
string Inventory[5];


int main(){



cout << "You are in the shop. What would you like to buy?";
cout << " You have " << Gold << " gold.";
cout << endl;
cout << "1\) Health potion: 2 gold.  2\) Mana Potion: 3 gold.";
cin >> Choice;
Shop(Choice);

cin.ignore();
cin.get();
return 0;
}

void Shop(int x){
 if(x==1){
   HealthPotion++;
   Gold = Gold-2;
   }
 if(x==2){
   ManaPotion++;
   Gold = Gold-3;
   }

}