The objective of this book is to provide a brief overview on the theory behind the physical phenomenon and to propose an algorithm, its C++ code, and the display of the solution. Furthermore, it is of paramount important to show to the reader how to easily modify the C++ code to accomodate a new but different problem that needs the same numerical method. The emphasis is put on the programming bearing in mind the requirement of the new algorithm of the problem under consideration. For sake of making this book easily understood we insist on the practical use of numerical methods and their applications. This is the reason why we propose, before each C++ code, to first explain the governing equations and then an algorithm is suggested. Subsequently, a clear and simple C++ code is proposed with the explanation of the most critical instructions, loops and functions and their role in the programme.