Since many C++ libraries have become widely-used by programmers. Pointers are one of the most powerful and flexible features used in C++. Pointers are particularly important for the analysis and design of data structures. The intention of this project is to compare the two implementation methods, "Closed" and "Open" by using two C++ Libraries. In this project, I designed and implemented a phonebook application by using a doubly linked list and a binary search tree as common data structures in the C++ libraries: C++ Standard Template Library (STL) and C++ Data Object Library (OrgC++). In order to explore the performance of the two styles of building data structure libraries in C++, I performed an objective comparison of two implementation methods in terms of ease of coding, time and space efficiency as well as the reliability. The applications were coded in C++