public BinaryTreeNode(int key)
{
this.key = key;
right = null;
left = null;
}
public BT()
{
root = null;
}
public BinaryTreeNode(int x)
{
this.data = x;
this.left = null;
this.right = null;
}
public BinaryTreeVik(int data)
{
this.root = new BinaryTreeNode(data);
}
public bool DeleteFromBST(int num)
{
try {
if (this.IsEmpty())
{
Console.WriteLine("Tree is empty, nothing to be removed");
return(false);
}
BinaryTreeNode current = this.root;
BinaryTreeNode previous = this.root;
while (current != null)
{
if (num == current.data)
{
Console.WriteLine("Giiven number {0} was found", num);
break;
}
previous = current;
if (num < current.data)
{
current = current.left;
}
else
{
current = current.right;
}
}
// Below if condition handles the special case when node to be delted is root node
if (current == this.root)
{
if (current.left == null || current.right == null)
{
if (current.left == null)
{
this.root = current.right;
}
else
{
this.root = current.left;
}
}
else
{
BinaryTreeNode newRoot = this.root.left;
BinaryTreeNode newRootPrev = this.root.left;
while (newRoot.right != null)
{
newRootPrev = newRoot;
newRoot = newRoot.right;
}
newRootPrev.right = null;
newRoot.left = this.root.left;
newRoot.right = this.root.right;
this.root = newRoot;
}
}
// Below code will be executed to handle the case when node to be deleted is not root node
else
{
if (current.left == null || current.right == null)
{
if (current.left == null)
{
previous.right = current.right;
}
else
{
previous.left = current.left;
}
}
else
{
BinaryTreeNode newCurrent = current.left;
BinaryTreeNode newPrevious = current.left;
while (newCurrent.right != null)
{
newPrevious = newCurrent;
newCurrent = newCurrent.right;
}
newCurrent.right = current.right;
current.left = null;
current.right = null;
if (previous.left == current)
{
previous.left = newCurrent;
}
else
{
previous.right = newCurrent;
}
}
}
return(true);
}
catch (NullReferenceException nre)
{
Console.WriteLine(nre.Message);
Console.WriteLine(nre.StackTrace);
return(false);
}
}
public BinaryTreeVik()
{
this.root = null;
}