Mega Code Archive
Max size as the parameter for a generic stack
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/* 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 <string>
#include <cstdlib>
#include <stdexcept>
template <typename T, int MAXSIZE>
class Stack {
private:
T elems[MAXSIZE]; // elements
int numElems; // current number of elements
public:
Stack(); // constructor
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 numElems == 0;
}
bool full() const { // return whether the stack is full
return numElems == MAXSIZE;
}
};
// constructor
template <typename T, int MAXSIZE>
Stack<T,MAXSIZE>::Stack ()
: numElems(0) // start with no elements
{
// nothing else to do
}
template <typename T, int MAXSIZE>
void Stack<T,MAXSIZE>::push (T const& elem)
{
if (numElems == MAXSIZE) {
throw std::out_of_range("Stack<>::push(): stack is full");
}
elems[numElems] = elem; // append element
++numElems; // increment number of elements
}
template<typename T, int MAXSIZE>
void Stack<T,MAXSIZE>::pop ()
{
if (numElems <= 0) {
throw std::out_of_range("Stack<>::pop(): empty stack");
}
--numElems; // decrement number of elements
}
template <typename T, int MAXSIZE>
T Stack<T,MAXSIZE>::top () const
{
if (numElems <= 0) {
throw std::out_of_range("Stack<>::top(): empty stack");
}
return elems[numElems-1]; // return last element
}
int main()
{
try {
Stack<int,20> int20Stack; // stack of up to 20 ints
Stack<int,40> int40Stack; // stack of up to 40 ints
Stack<std::string,40> stringStack; // stack of up to 40 strings
// manipulate stack of up to 20 ints
int20Stack.push(7);
std::cout << int20Stack.top() << std::endl;
int20Stack.pop();
// manipulate stack of up to 40 strings
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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