Find path from root to leaf with a given sum

/*
 Given a tree and a sum, return true if there is a path from the root
 down to a leaf, such that adding up all the values along the path
 equals the given sum.
 Strategy: subtract the node value from the sum when recurring down,
 and check to see if the sum is 0 when you run out of tree.
*/
int hasPathSum(struct node* node, int sum) {
  // return true if we run out of tree and sum==0
  if (node == NULL) {
    return(sum == 0);
  }
  else {
  // otherwise check both subtrees
    int subSum = sum - node->data;
    return(hasPathSum(node->left, subSum) ||
           hasPathSum(node->right, subSum));
  }
}