What do the statements starting with # do?
A13: Before the compiler ever sees the file containing your program, another tool, called the preprocessor, works on it a bit. In fact, the preprocessor creates a whole new source file, based on your source file, but with some work done to it. What it does to the file depends on what you tell it to do. Why, you say, I did not tell it to do anything… Ah, but you did. Every time you write a statement starting with ‘#’, preprocessor treats it as a request to do something. The following are some of the valid ways to talk to the preprocessor.
