Answer :

Answer:

Node * leftmost(Node * root)

{

 if(root==NULL)

return NULL;

return leftmost(root->left);

}

Explanation:

This is the function to return the leftmost node of the Binary tree in C++.Return type of the function is Node.If root is NULL then we are returning NULL because there is no tree.Now we have to make a recursive call on root->left.