/*
** $Id: stack.c 739 2008-02-09 00:58:20Z phf $
*/

#include <assert.h>
#include "stack.h"

// maximum size of the stack

#define SIZE 8

// our internal representation of the stack; note that "index"
// always points to the current "top" of the stack, so for an
// empty stack, we have index == -1

static int index = -1;
static int stack[SIZE];

// the remaining functions are hopefully obvious enough? make
// sure you ask if anything is unclear!

void push(int element)
{
  assert(index < SIZE-1);
  index += 1;
  stack[index] = element;
}

void pop(void)
{
  assert(index > -1);
  index -= 1;
}

int top(void)
{
  assert(index > -1);
  return stack[index];
}

int size(void)
{
  return index+1;
}

int capacity(void)
{
  return SIZE;
}