Introduction to C Libraries - math.h and More


C libraries provide a rich set of functions for various tasks, from mathematical calculations to file handling and more. In this guide, we'll introduce C libraries, with a focus on the `math.h` library. We'll explain the purpose of libraries, how to use them, and provide sample code to illustrate their usage.

What Are C Libraries?

C libraries are collections of pre-written functions and definitions that can be used in C programs. They provide a way to reuse code and avoid reinventing the wheel for common tasks. The `math.h` library, for example, contains mathematical functions like square roots, trigonometric calculations, and more.

Sample Code

Let's explore some examples of using the `math.h` library in C:

Calculating Square Roots

#include <stdio.h>
#include <math.h>
int main() {
double number = 25.0;
double square_root = sqrt(number);
printf("Square root of %.2f is %.2f\\n", number, square_root);
return 0;

Trigonometric Calculations

#include <stdio.h>
#include <math.h>
int main() {
double angle = 45.0; // Angle in degrees
double radians = angle * (M_PI / 180.0);
double sine_value = sin(radians);
double cosine_value = cos(radians);
printf("Sine of %.2f degrees: %.2f\\n", angle, sine_value);
printf("Cosine of %.2f degrees: %.2f\\n", angle, cosine_value);
return 0;

Using C Libraries

To use C libraries in your programs, include the appropriate library header using `#include`, and then link your program with the library during compilation. For example, to use the `math.h` library, you might compile your program with:

gcc myprogram.c -lm

The `-lm` flag tells the compiler to link with the `math` library.


C libraries, such as `math.h`, provide a wealth of functions to simplify and enhance your C programs. This guide introduced the concept of C libraries, explained how to use the `math.h` library, and provided sample code to demonstrate its usage. As you continue your C programming journey, you'll find libraries to be indispensable for building feature-rich and efficient applications.