class pair {
  bool mAmISet;
  int mIndexInBoard;
};

pair first, second;

void on_user_click(int index) // index is which tile the user clicked.
{
  if (first.mAmISet == false) // not set so we should set the first guy.
  {
    first.mAmISet = true;
    first.mIndexInBoard = index;
  } else if (second.mAmISet == false)
  {
    // if it hits this case it means first guy is already set. if the first
    // case is true but this case is false it means I have the first tile
    // selected but not the second.

    second.mAmISet = true;
    second.mIndexInBoard = index;

    if (myBoard[index].type == myBoard[first.mIndexInBoard].type)
    {
      // the type is the same so kkeep them revealed.

      // also reset the bools so that it never hits the last case
      first.mAmIset = false;
      second.mAmISet = false;
    } else
    {
      // not equals, set the borders red.
    }

  } else
  {
    // so here is when both are selected now, so we should check to see if there
    // is a matching pair.
    if (myBoard[index].type == myBoard[first.mIndexInBoard].type)
    {
      // the type is the same so kkeep them revealed.
    } else
    {
      // type not the same, hide both.
    }

    // reset the first and second selection grid so nothing is selected.
    first.mAmIset = false;
    second.mAmISet = false;
  }
}