Mega Code Archive
Template string stack
<![CDATA[
/* 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 <iostream>
#include <cstdlib>
#include <vector>
template <typename T>
class Stack {
private:
std::vector<T> 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>
void Stack<T>::push (T const& elem)
{
elems.push_back(elem); // append copy of passed elem
}
template<typename T>
void Stack<T>::pop ()
{
if (elems.empty()) {
throw std::out_of_range("Stack<>::pop(): empty stack");
}
elems.pop_back(); // remove last element
}
template <typename T>
T Stack<T>::top () const
{
if (elems.empty()) {
throw std::out_of_range("Stack<>::top(): empty stack");
}
return elems.back(); // return copy of last element
}
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
}
int main()
{
try {
Stack<int> intStack; // stack of ints
Stack<std::string> stringStack; // stack of strings
// manipulate int stack
intStack.push(7);
std::cout << intStack.top() << std::endl;
intStack.pop();
// manipulate string stack
stringStack.push("hello");
std::cout << stringStack.top() << std::endl;
stringStack.pop();
}
catch (std::exception const& ex) {
std::cerr << "Exception: " << ex.what() << std::endl;
return EXIT_FAILURE; // exit program with ERROR status
}
}
7
hello
Exception: Stack::pop(): empty stack
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