/in/foo.cc:2:6: error: 'BinTree' has not been declared
 void BinTree::Order()
      ^~~~~~~
/in/foo.cc: In function 'void Order()':
/in/foo.cc:4:8: error: 'root' was not declared in this scope
  Order(root);
        ^~~~
/in/foo.cc: At global scope:
/in/foo.cc:6:6: error: 'BinTree' has not been declared
 void BinTree::Order(Node *p)
      ^~~~~~~
/in/foo.cc:6:21: error: variable or field 'Order' declared void
 void BinTree::Order(Node *p)
                     ^~~~
/in/foo.cc:6:21: error: 'Node' was not declared in this scope
/in/foo.cc:6:27: error: 'p' was not declared in this scope
 void BinTree::Order(Node *p)
                           ^
/in/foo.cc: In function 'int main(int, char**)':
/in/foo.cc:15:2: error: 'BinTree' was not declared in this scope
  BinTree T("ABD**E**C**");
  ^~~~~~~
/in/foo.cc:16:2: error: 'T' was not declared in this scope
  T.Order();
  ^