Generic stack based on vector : generic stack « template « C++ Tutorial

1. C++ Tutorial
2. template
3. generic stack

/* The following code example is taken from the book
 * "C++ Templates - The Complete Guide"
 * by David Vandevoorde and Nicolai M. Josuttis, Addison-Wesley, 2002
 *
 * (C) Copyright David Vandevoorde and Nicolai M. Josuttis 2002.
 * Permission to copy, use, modify, sell and distribute this software
 * is granted provided this copyright notice appears in all copies.
 * This software is provided "as is" without express or implied
 * warranty, and with no claim as to its suitability for any purpose.
 */
#include <iostream>
#include <deque>
#include <cstdlib>
#include <vector>
#include <stdexcept>

template <typename T, typename CONT = std::vector<T> >
class Stack {
  private:
    CONT elems;               // elements

  public:
    void push(T const&);      // push element
    void pop();               // pop element
    T top() const;            // return top element
    bool empty() const {      // return whether the stack is empty
        return elems.empty();
    }
};

template <typename T, typename CONT>
void Stack<T,CONT>::push (T const& elem)
{
    elems.push_back(elem);    // append copy of passed elem
}

template <typename T, typename CONT>
void Stack<T,CONT>::pop ()
{
    if (elems.empty()) {
        throw std::out_of_range("Stack<>::pop(): empty stack");
    }
    elems.pop_back();         // remove last element
}

template <typename T, typename CONT>
T Stack<T,CONT>::top () const
{
    if (elems.empty()) {
        throw std::out_of_range("Stack<>::top(): empty stack");
    }
    return elems.back();      // return copy of last element
}


int main()
{
    try {
        // stack of ints:
        Stack<int> intStack;

        // stack of doubles which uses a std::deque<> to manage the elements
        Stack<double,std::deque<double> > dblStack;

        // manipulate int stack
        intStack.push(7);
        std::cout << intStack.top() << std::endl;
        intStack.pop();

        // manipulate double stack
        dblStack.push(42.42);
        std::cout << dblStack.top() << std::endl;
        dblStack.pop();
        dblStack.pop();
    }
    catch (std::exception const& ex) {
        std::cerr << "Exception: " << ex.what() << std::endl;
        return EXIT_FAILURE;  // exit program with ERROR status
    }
}

7
42.42
Exception: Stack<>::pop(): empty stack