stack.cpp

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#include "stack.h"

Stack::Stack( int currentSize )
{
	_HEAD = new char[currentSize];
	_TAIL = 0;
	_STACK_SIZE = currentSize ;
}


int Stack::_Resize_Stack( int newSize )
{
	char* _NEW_HEAD = NULL; 
	_NEW_HEAD = new char[newSize];

	if ( _NEW_HEAD == NULL )
		return -1;
	
	for( int counter = 0; counter < _TAIL; counter++ )
	{
		_NEW_HEAD[counter] = _HEAD[counter];
	}
	
	delete _HEAD;
	_HEAD = _NEW_HEAD;
	_STACK_SIZE = newSize;

	return 0;
}


Stack::~Stack()
{
	delete _HEAD;
}


void Stack::Push( char myData )
{
	if ( _STACK_SIZE == (_TAIL - 1) )
	{
		_Resize_Stack( _STACK_SIZE * 2 );
	}
	
	_HEAD[_TAIL++] = myData;
}


char Stack::Pop()
{
	if ( _TAIL == 0 )
		return NULL;

	return _HEAD[--_TAIL];
}