Answer


Near the top of almost every C program you'll find some ``#include'' lines-in our C program outline, there are two such lines. These lines are special, in that as far as we are concerned, they don't really ``do'' anything in the program.

Instead, ``#include'' lines are special instructions for the C compiler. They tell the compiler about other functions that we are invoking in our program.

Take a look at our sample C program again. The line ``#include <stdio.h>'' tells the compiler that we are going to use the functions that do input and output. The abbreviation stdio stands for ``standard input/output.''

The line ``#include <math.h>'' tells the compiler that we are going to use some math functions, such as sine and cosine. (In C those functions are called sin and cos.)

Return to lesson.



Eric N. Eide
Hamlet Project
Department of Computer Science
University of Utah