//fast version

int Tree::BranchHeight(TreeNode *ptrNode)

{

if (ptrNode == NULL)

return 0;

else

{

int lHight, rHight;

lHight= BranchHeight(ptrNode->Left);

rHight= BranchHeight(ptrNode->Right);

if (lHight > rHight )

return lHight+1;

else

return rHight+1;

}

}

int Tree::Height()

{

return BranchHeight(Root);

}