/*
 * implementation of integer stack
 *
 */

#include "intStack.h"
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>

boolean push(intStack *stack, int value) 
{
  if (stack->top > stack->max - 2) /* stack is full */
    return FALSE;
  else {
    stack->top++;
    stack->valueList[stack->top] = value;
    return TRUE;
  }
}

int pop(intStack *stack)
{
    assert(!empty(stack)); /* crash informatively otherwise */
    return stack->valueList[stack->top--]; /* evaluate, then decrement */
}

int peek(intStack *stack)
{
    assert(!empty(stack)); /* crash informatively otherwise */
    return stack->valueList[stack->top]; /* no decrement */
}

boolean initialize(intStack *stack, int capacity)
{
    stack->valueList = (int *) malloc(capacity * sizeof(int));
    if (stack->valueList == NULL)
	return FALSE;
    else {
	stack->top = -1; /* empty stack */
	stack->max = capacity;
	return TRUE;
    }
}

boolean destroy(intStack *stack)
{
    if (stack->valueList) { /* it's non-NULL */
	free (stack->valueList);
	stack->valueList = NULL;
	stack->top = -1;
	stack->max = 0;
	return TRUE;
    }
    else {
	return FALSE;
    }
}


int count(intStack* stack)
{
    return stack->top + 1;
}

boolean empty(intStack *stack)
{
    return stack->top < 0;
}

boolean full(intStack *stack)
{
    return stack->top > stack->max - 2;
}

void printStack(intStack *stack)
{
  int i; /* loop index */
  for (i = 0; i <= stack->top; i++) {
    printf("%d  ", stack->valueList[i]);
  }
}