If any input value (or commands)is passed through the command prompt at the time of running of program is known as command line argument. It is a concept to passing the arguments to the main() function by using command prompt. Preprocessor directives are lines included in a program that being with the character #, which make them different from a typical source code text. They are invoked by the compiler to process some programs before compilation.
command–line arguments, Preprocessor commands