C++ Preprocessor

C++ > Preprocessor 

Preprocessor performs preliminary operations on C++ files before they are passed to the compiler. 

• insert files
• compiler error messages
• conditionally compile code 

The preprocessor is a text processor that manipulates the text of a source file as part of the first phase of translation. The compiler ordinarily invokes the preprocessor in its first pass, but the preprocessor can also be invoked separately to process text without compiling.