# C Program for Fibonacci Series

Summary: in this tutorial, you will learn how to develop a C program for Fibonacci series using recursion and iteration techniques.

## Introduction to Fibonacci numbers

In mathematics, the Fibonacci numbers, or Fibonacci series,  are the numbers that are in the following sequence:

0,1,1,2,3,5,6,13,21,34,55,89,…

The first number in the Fibonacci sequence is 0, the second number is 1. The subsequent number is the result of the sum of the previous two e.g., third number 1 = 1+0, fourth number 2=1+1, fifth number 3 = 2+1, etc.

The Fn number is defined as follows:

Fn = Fn-1 + Fn-2,

with the seed values:

F0 = 0, F1 = 1.

## C Programs for Fibonacci Series

### C Program for Fibonacci series using recursion

The first simple approach of developing a function that calculate the nth number in the Fibonacci series using a recursive function. The following is Fibonacci series program in c:

Now if you enter 15, the program will display the following output:

### C Program for Fibonacci series using iteration

The Fibonacci series program using recursion technique is less efficient if you want to display a long series because the number of function calls increase and the chance of a stack overflow error may occur.

The following is the program that displays the Fibonacci series using iteration technique:

In this tutorial, you have learned how to develop a C program for Fibonacci series using recursion and iteration techniques.