From a purely object-oriented perspective, "copy semantics" is the right way to preserve control over object ownership. But in those scenarios where ownership becomes irrelevant, C++11 "move semantics ...

// unbalanced_binary_tree.h #ifndef UNBALANCED_BINARY_TREE_H #define UNBALANCED_BINARY_TREE_H // uncomment this line to enable move semantics; comment it to disable it. //#define MOVE_SEMANTICS ...