/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* 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 <exception>
using namespace std;
template <class T>
class Stack {
protected:
std::deque<T> c; // container for the elements
public:
/* exception class for pop() and top() with empty stack
*/
class ReadEmptyStack : public std::exception {
public:
virtual const char* what() const throw() {
return "read empty stack";
}
};
// number of elements
typename std::deque<T>::size_type size() const {
return c.size();
}
// is stack empty?
bool empty() const {
return c.empty();
}
// push element into the stack
void push (const T& elem) {
c.push_back(elem);
}
// pop element out of the stack and return its value
T pop () {
if (c.empty()) {
throw ReadEmptyStack();
}
T elem(c.back());
c.pop_back();
return elem;
}
// return value of next element
T& top () {
if (c.empty()) {
throw ReadEmptyStack();
}
return c.back();
}
};
int main()
{
try {
Stack<int> st;
// push three elements into the stack
st.push(1);
st.push(2);
st.push(3);
// pop and print two elements from the stack
cout << st.pop() << ' ';
cout << st.pop() << ' ';
// modify top element
st.top() = 77;
// push two new elements
st.push(4);
st.push(5);
// pop one element without processing it
st.pop();
/* pop and print three elements
* - ERROR: one element too many
*/
cout << st.pop() << ' ';
cout << st.pop() << endl;
cout << st.pop() << endl;
}
catch (const exception& e) {
cerr << "EXCEPTION: " << e.what() << endl;
}
}
/*
3 2 4 77
EXCEPTION: read empty stack
*/
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