#include <stdlib.h>
#include "intStack.h"	// Define stack object and declare stack functions



/* ==================================================================
   intStackInitialize(stackObj, N): Create a stack for N int's
   ================================================================== */
void intStackInitialize(intStack *stackObj, int N)
{
   stackObj->s = (int *) calloc( sizeof(int), N );
   stackObj->stackTop = -1;
}


/* ==================================================================
   intStackPush(stackObj,x): push x on stack
   ================================================================== */
void intStackPush( intStack *stackObj, int x)
{
   (stackObj->stackTop)++;                    // Increment stack top
   stackObj->s[ stackObj->stackTop ] = x;     // Store x in stack top
}


/* ==================================================================
   intStackPop(stackObj): pop stack  top and return it
   ================================================================== */
int  intStackPop( intStack *stackObj)
{
   int r;

   r = stackObj->s[ stackObj->stackTop ];     // Save return value in r
   (stackObj->stackTop)--;                    // Decrement stack top
   
   return(r);
}

/* ==================================================================
   intStackPeek(stackObj): peek at top of stack
   ================================================================== */
int  intStackPeek( intStack *stackObj)
{
   return stackObj->s[ stackObj->stackTop ];
}