// ################################################################################//// name:          stack.cc//// author:        Martin Pelikan//// purpose:       the definition of a class IntStack (a stack for int)//// last modified: February 1999//// #################################################################################include <stdio.h>#include <stdlib.h>#include "stack.h"#include "memalloc.h"// ================================================================================//// name:          IntStack::Intstack//// function:      the constructor for the class Intstack; allocates the memory for //                a maximal number of integers to store//// parameters:    max..........a maximal number of integers to store//// returns:       (none)//// last modified: February 1999//// ================================================================================IntStack::IntStack(int max){  maxSize = max;  size    = 0;  s = (int*) Calloc(max,sizeof(int));}// ================================================================================//// name:          IntStack::~Intstack//// function:      the destructor for the class Intstack; frees the memory allocted //                for the stored integers//// parameters:    (none)//// returns:       (none)//// last modified: February 1999//// ================================================================================IntStack::~IntStack(){  Free(s);}// ================================================================================//// name:          IntStack::push//// function:      stores an integer on the top of the stack, crashes when the stack//                is full (with exit code -1)//// parameters:    x............a number to store//// returns:       (int) the stored number//// last modified: February 1999//// ================================================================================int IntStack::push(int x){  if (size>=maxSize)    {      fprintf(stderr,"ERROR: push method called for a full stack!\n");      exit(-1);    }  return s[size++]=x;}// ================================================================================//// name:          IntStack::pop//// function:      pops the integer on the top of the stack and gets rid of it; //                crashes when the stack is empty (with exit code -1)//// parameters:    (none)//// returns:       (int) the number from the top of the stack//// last modified: February 1999//// ================================================================================int IntStack::pop(){  if (size>0)    return s[--size];  else    {      fprintf(stderr,"ERROR: pop method called for an empty stack!\n");      exit(-1);    }  return 0;}// ================================================================================//// name:          IntStack::empty//// function:      checks whether the stack is empty//// parameters:    (none)//// returns:       (int) true if the stack is empty//// last modified: February 1999//// ================================================================================int IntStack::empty(){  return (size==0);}// ================================================================================//// name:          IntStack::notEmpty//// function:      checks whether the stack is not empty//// parameters:    (none)//// returns:       (int) true if the stack is not empty//// last modified: February 1999//// ================================================================================int IntStack::notEmpty(){  return size;}// ================================================================================//// name:          IntStack::full//// function:      checks whether the stack is full//// parameters:    (none)//// returns:       (int) true if the stack is full//// last modified: February 1999//// ================================================================================int IntStack::full(){  return (size==maxSize);}// ================================================================================//// name:          IntStack::getSize//// function:      checks the size of the stack//// parameters:    (none)//// returns:       (int) the current size of the stack//// last modified: February 1999//// ================================================================================int IntStack::getSize(){  return size;}