Binary serach tree comapre C++

I have written the code for binary search tree in XCODE in C++, the algorithm is fine, but interface may be wrong -it gives me error no viable conversion from BST to compare::node. Can you fix it. I have defined a public class within BST and called it within main class BST{ public: bool isame(node*a, node *b){ if (a == NULL && b == NULL) return true; else if (a == NULL || b == NULL) return false; else if ((a->left == b->left) && (a->right == b->right)) return true; else return false; } }; int main(int argc, const char * argv[]) { compare mybst; BST t; [login to view URL](10); [login to view URL](25); [login to view URL](95); [login to view URL](23); [login to view URL](50); [login to view URL](); BST q; [login to view URL](12); [login to view URL](27); [login to view URL](95); [login to view URL](3); [login to view URL](50); [login to view URL](); cout<<[login to view URL](t,q)<<endl; return 0; }