C preprocessor, file read and write

Preprocessor

Reference links: https://www.runoob.com/cprogramming/c-preprocessors.html
done before the pre-processor is then variation some work

include a source file containing code for

Common are #include <stdio.h>is to get stdio.h from the system library and added to the current text. And #include "header.h"it tells the preprocessor (cpp) header.h add files from the current directory to the current text

defind define macros

Macro mean everyone knows it is similar to a constant as

#define COLOR "blue"

There cancel the macro definitionundef

Predefined macros

Including some dates, current directory, etc., can not be modified

Preprocessor operator

Parameterized macro

File read and write

https://www.runoob.com/cprogramming/c-file-io.html