#include <string>
#include <vector>

using namespace std;

class Stack
{
public:
    Stack();

    void push(string item);
    string pop();

private:
    vector<string> stack;
};

Stack::Stack() {}

void Stack::push(string item)
{
    stack.push_back(item);
}

string Stack::pop()
{
    string top_item = stack.back();
    stack.pop_back();
    return top_item;
}

int main()
{
    Stack stk;

    stk.push("A");
    stk.push("B");
    stk.push("C");

    stk.erase(stk.begin() + 1);  // not allowed
}