Why we use # file in c & c++ ??

Answer 1

#include is a part of C/C++ preprocessor, which makes standard C/C++ library functions accessible/available to your code.

Answer 2

Hi.
The commands that are introduced using # symbol are telling the pre-compiler to put the code written in the named file/header at this point before the compiler translates the human readable code to machine readable/executable instructions.
This increases readability since you can put code in separate files. Furthermore, it makes code re-usable since you can include header files in multiple projects.
Usually including iostream is done by

#include <iostream>

Cheers.

Answer 3

9n_mn

Answer 4

I'm new to c++ and I'd you to help me to calculate this question "how to calculate for standard deviation using file handling?"