Preprocessors
C Preprocessors are the header of the file
- contains C function declarations and macro definitions to be shared between several source files.
- In essence, they are like importing modules.
- ex.
stdio.h
– Defines core input and output functions - In C, all lines that start with # are processed by preprocessor which is a program invoked by the compiler
- a preprocessor takes a C program and produces another C program without any
#
- a preprocessor takes a C program and produces another C program without any
- When we use
include
directive, the contents of included header file (after preprocessing) are copied to the current file.<
and>
instruct the preprocessor to look in the standard folder“
and“
instruct the preprocessor to look into the current folder
- When we use
define
for a constant, the preprocessor produces a C program where the defined constant is searched and matching tokens are replaced with the given expression- ex.
#define max 100
—max
is searched for in the program, and is replaced with100
- ex.