What is the function of each header?

Question

What's the function of each header possibilities (isotream, conio, upstream , stdio, manip)?

Answer 1

Each header file has the prototypes of the functions and the classes that u are going to use in your code.
For example:

When you use printf() function then its declaration is present in <stdio.h>, hence while executing this printf() line of u=your C code the complier knows that there is function named printf() by this header file.

Answer 2

Wow thanks, I got it! Very usefull answer!