Diameter of a Tree

int Diameter(TreeNode t, int* height)
{
    int lh = 0, rh = 0;
    int leftD = 0, rightD = 0;

    if(t == NULL)
    {
        *height = 0;
        return 0; /* diameter is also 0 */
    }

    leftD =  Diameter (root->left, &lh);
    rightD =  Diameter (root->right,&rh);

    /* Height of current node is max of heights of left and
    right subtrees plus 1*/
    *height = max(lh, rh) + 1;

    return max(lh + rh + 1, leftD, rightD);
}