This book introduces the object oriented programming concepts and demonstrates their use in building correct and efficient codes using the syntactic features of C++. Given the fact that most of the modern high-level programming languages have some object oriented programming capability, the book uses the linguistic features of C++ to present the inherent mechanisms of object oriented programming and the code building process which use them in such a way that what is learned from this book can be extended to other programming languages like Perl, Java, Python, C#, and many others. Those "inherent mechanisms" of object oriented programming are abstraction, inheritance, and polymorphism. We all know that an effective use of any concept in science or engineering for solution of practical problems always requires a mastery of certain body of knowledge over and about that concept which, in the case of object oriented programming as a solution methodology, embodies abstraction and inheritance and polymorphism. The book gives a detailed coverage of these programming mechanisms and backs the treatment with ample demonstrations of their use in code building process. That process, as emphasized in this book, always passes through the three phases: object oriented analysis phase (OOA), object oriented design phase (OOD), and object oriented programming phase (OOP.) What results from this process is an object oriented program, a program which is populated with real-world objects which interact in some ways to solve problems. Most of the programming demonstrations are complete programs which are ready to be compiled and executed. This book also gives a detailed coverage of how the program's objects relate with one another in the course of their interaction to solve problems. That relationship is afforded with the programming mechanisms of inheritance and composition. In the case of C++, for example, there is another relationship called a friend of class which is a colorful name given to any code which does not belong in the class but to which the class grants a privilege to access its private members. Because a friend of class can access the private properties of its class, it presents a serious security risk not only to the class itself and the program that uses the class but also to the systems (computers, networks, etc.) on which the program runs. (Every programming feature - not only friend of class - presents some security risks which are often exploited by "bad people" to hack the systems or infect them with some malware codes - viruses, worms, Trojans, etc.) This book does not dwell on the security "holes" in the object oriented programming features nor on the dangers they pose. Such will come later -- in more advanced texts. First things first: the only purpose of this book, the sole reason for its existence, is to use the language of C++ to introduce the object oriented programming concepts and demonstrate their application in code buildings.
