stack2.hpp

C++ Templates 完全导引范例asics

/* 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 <deque>
#include <string>
#include <stdexcept>
#include "stack1.hpp"

template<>
class Stack<std::string> {
  private:
    std::deque<std::string> elems;  // elements

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

void Stack<std::string>::push (std::string const& elem)
{
    elems.push_back(elem);    // append copy of passed elem
}

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

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