// Play the game.
private void playButton_Click(object sender, EventArgs e)
{
AnimalNode node = Root;
for (; ;)
{
// See if this is an internal or leaf node.
if (node.YesChild == null)
{
// It's a leaf node.
ProcessLeafNode(node);
return;
}
// It's an internal node.
// Ask the node's question and move to the appropriate child node.
if (MessageBox.Show(node.Question, "Question",
MessageBoxButtons.YesNo, MessageBoxIcon.Question)
== DialogResult.Yes)
{
node = node.YesChild;
}
else
{
node = node.NoChild;
}
}
}
// Process a leaf node.
private void ProcessLeafNode(AnimalNode leaf)
{
// This is a leaf node. Guess the animal.
string text = "Is your animal " + Article(leaf.Question) +
" " + leaf.Question + "?";
if (MessageBox.Show(text, leaf.Question,
MessageBoxButtons.YesNo, MessageBoxIcon.Question)
== DialogResult.Yes)
{
// We got it right. Gloat and exit.
MessageBox.Show("Victory is mine!", "I Win!",
MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
return;
}
// We got it wrong.
// Ask the user for the new animal.
PromptForm dialog = new PromptForm();
dialog.promptLabel.Text = "What is your animal?";
dialog.responseTextBox.Clear();
dialog.ShowDialog();
string newAnimal = dialog.responseTextBox.Text.ToLower();
// Ask the user for a new question.
dialog.promptLabel.Text =
"What question could I ask to differentiate between " +
Article(leaf.Question) + " " + leaf.Question + " and " +
Article(newAnimal) + " " + newAnimal + "?";
dialog.responseTextBox.Clear();
dialog.ShowDialog();
string newQuestion = dialog.responseTextBox.Text;
// See if the question's answer is true for the new animal.
bool newAnimalIsTrue =
MessageBox.Show("Is the answer to this question true for " +
Article(newAnimal) + " " + newAnimal + "?",
"New Animal", MessageBoxButtons.YesNo,
MessageBoxIcon.Question) == DialogResult.Yes;
// Update the knowledge tree.
string oldAnimal = leaf.Question;
leaf.Question = newQuestion;
if (newAnimalIsTrue)
{
leaf.YesChild = new AnimalNode(newAnimal);
leaf.NoChild = new AnimalNode(oldAnimal);
}
else
{
leaf.YesChild = new AnimalNode(oldAnimal);
leaf.NoChild = new AnimalNode(newAnimal);
}
}
// Create an initial tree.
private void Form1_Load(object sender, EventArgs e)
{
Root = new AnimalNode("Is it a mammal?");
Root.YesChild = new AnimalNode("dog");
Root.NoChild = new AnimalNode("fish");
}
