private void UpdateButtons()
{
buttons.Update();
int letterButtonIndex = DataUtil.IndexOf(view.letterButtons, buttons.view.target);
if (0 <= letterButtonIndex)
{
model.Toggle(letterButtonIndex);
}
else if (view.exitButton == buttons.view.target)
{
model.Exit();
}
else if (view.hintButton == buttons.view.target)
{
model.Hint();
}
}