# Finding the height of a binary tree recursively

The height of a node in a binary tree is simply the maximum of the height of its left and right subtrees, plus one.

This lends itself to a simple recursive algorithm for finding the height of a binary tree.

static int max(int a, int b)
{
if (a >= b) {
return a;
}
return b;
}

unsigned int binarytree_height_recursive(const btnode *node)
{
unsigned int height = 0;
if (node->left || node->right) {
height = max(node->left ? binarytree_height_recursive(node->left) : 0,
node->right ? binarytree_height_recursive(node->right) : 0) + 1;
}
return height;
}

unsigned int binarytree_height(const binarytree *tree)
{
unsigned int height = 0;
if (tree->root) {
height = binarytree_height_recursive(tree->root);
}
return height;
}