void StackPush(stackT *StackP, int element)
{
    if(StackP->elems == StackP->maxSize)
    {
        int *moreContents = (int*)realloc(StackP->contents, (StackP->maxSize+10)*sizeof(int));
        StackP->contents = moreContents;
    }
    StackP->elems = StackP->elems+1;
    StackP->lastElem = element;
    StackP->contents[++StackP->top] = element;
}

int StackPop(stackT *StackP)
{
    int lastTop;
    if(StackIsEmpty(StackP))
    {
        fprintf(stderr, "Can't pop element form stack: stack is empty\n");
        exit(1);
    }
    lastTop = StackP->top -1;
    StackP->elems = StackP->elems-1;
    if(lastTop == -1)
        StackP->lastElem = 0;
    else
        StackP->lastElem = StackP->contents[lastTop];
    return StackP->contents[StackP->top--];
}