// Paints the current node, then recursively paints children, until all child nodes are null.
private void PaintNode(BinaryTreeNode node, int treeCenterX, Graphics graphics, int parentX, int parentY)
{
if (node != null)
{
int adjustedX = (int)(node.GetX() * BinaryTreeNode.SIZE * Math.Pow(2, treeDepth) / 2);
int adjustedY = (int)(node.GetY() * BinaryTreeNode.SIZE * 2);
if (parentX != -1 && parentY != -1)
{
graphics.DrawLine(drawingPen,
treeCenterX + parentX,
parentY,
treeCenterX + adjustedX + BinaryTreeNode.SIZE / 2,
adjustedY);
}
graphics.DrawEllipse(drawingPen, treeCenterX + adjustedX,
adjustedY,
BinaryTreeNode.SIZE,
BinaryTreeNode.SIZE);
graphics.DrawString("" + node.GetValue(),
drawingFont,
drawingPen.Brush,
treeCenterX + adjustedX + BinaryTreeNode.SIZE / 4,
(int)(node.GetY() * BinaryTreeNode.SIZE * 2) + BinaryTreeNode.SIZE / 4);
foreach (BinaryTreeNode n in node.GetChildren())
{
PaintNode(n, treeCenterX, graphics, adjustedX + BinaryTreeNode.SIZE / 2, adjustedY + BinaryTreeNode.SIZE);
}
}
}
// The recursive method for adding a node to the tree.
private void AddNode(BinaryTreeNode thisNode, BinaryTreeNode newNode, int tempDepth)
{
// Increment the current depth of the tree traversal
tempDepth++;
// If the new value is less than or equal to the current value, add to the left, otherwise add to the right.
BinaryTreeNode.ChildNode nextNode =
(newNode.CompareTo(thisNode) > 0) ?
BinaryTreeNode.ChildNode.RIGHT :
BinaryTreeNode.ChildNode.LEFT;
// If the chosen child node is null, set it to the new value, otherwise continue the recursion.
if (thisNode.GetChildNode(nextNode) == null)
{
newNode.SetPosition(thisNode.GetX() + ((int)nextNode * 2 - 1) * (Math.Pow(2, -tempDepth)), thisNode.GetY() + 1);
thisNode.SetChildNode(nextNode, newNode);
// If we are currently deeper than the known depth of the tree, increase the tree depth and calculate the tree width.
if (tempDepth + 1 > treeDepth)
{
treeDepth = tempDepth + 1;
treeWidth = (int)Math.Pow(2, treeDepth);
}
}
else
{
AddNode(thisNode.GetChildNode(nextNode), newNode, tempDepth);
}
}