In a broad sense, computer programs are sequences of instructions meant to be executed in a certain order, so as to perform specific tasks or solve the given problems. The ways in which the same task can be properly coded are literally innumerable, being largely a matter of programming style and experience. On a higher level of abstraction, a program can be conceived as a collection of functions performing welldefined tasks. One of the functions, calledmain program, is compelling and controls the overall execution of the program, while the other functions carry out subordinated tasks. The number, functionality, and implementation of the program units are not imposed by any strict rules and may depend on various factors, not in the least on the programmer’s proficiency.