The C pre-processor is used to scan and modify a source code before its compilation. The line starting with the SYMBOL # followed by the DIRECTIVE name, in the source code, is KNOWN as pre-processor directive. Pre-processor directive invoked by the compiler to process some code before the compilation process.

Each line in code can have a single pre-processor directive

Pre-processor directive does not include a semicolon at the end.

Header FILES are the files which contain macro definitions and functions definition. It used with pre-processor directives with a file extension of ".h."

There are two types of header files in C:

System header files: These header files come with the compiler

User-created header files: These files are WRITTEN by the programmer.

Following are some mainly used header files in C

#include<stdio.h>

#include<conio.h>

#include<stdlib.h>

#include<string.h>

#include<math.h>, and many more.

The C pre-processor is used to scan and modify a source code before its compilation. The line starting with the symbol # followed by the directive name, in the source code, is known as pre-processor directive. Pre-processor directive invoked by the compiler to process some code before the compilation process.

Each line in code can have a single pre-processor directive

Pre-processor directive does not include a semicolon at the end.

Header files are the files which contain macro definitions and functions definition. It used with pre-processor directives with a file extension of ".h."

There are two types of header files in C:

System header files: These header files come with the compiler

User-created header files: These files are written by the programmer.

Following are some mainly used header files in C

#include<stdio.h>

#include<conio.h>

#include<stdlib.h>

#include<string.h>

#include<math.h>, and many more.