#include <vector>

class stackEmptyException : public std::exception {
  public:
    stackEmptyException() noexcept
    {}

    const char* what() const { return "Attempt to pop empty stack."; }
};

template <typename T,typename Container = std::vector<T> >
class stack {
  public:
    stack() {}
    
    bool isEmpty() const { return body.empty(); }

    void push(const T& item) {
      body.push_back(item);
    }

    const T& top() {
      return body.back();
    }

    void pop() {
      if(this.isEmpty()) throw stackEmptyException();
      body.pop_back();
    }

  private:
    Container body;
};