Binary Search Tree Algorithm

procedure insertion( : binary search tree, : item)
root of
{a vertex not present in has the value null }
while and
   if then
    if left child of then left child of
    else add new vertex as a left child of and set
  else
    if right child of then right child of
    else add new vertex as a right child of and set
if root of then add a vertex to the tree and label it with
else if is null or then label new vertex with and let be this new vertex
return { = location of }