## In this article, you’ll learn about C Fibonacci series, how it works and how can we use it.

**What are C Fibonacci series and Fibonacci series logic?**

A series of numbers in which each sequent number is the sum of its two previous numbers is known as *Fibonacci series* and each number is called *Fibonacci numbers*.

#### Algorithm

**Algorithm for Fibonacci series. Fn = Fn-2 + Fn -1.**

To understand this example, you should have the knowledge of following C programming topic:

- for Loop
- while and do…while Loop

First, two numbers of the Fibonacci series is 0 and 1. From 3rd number onwards, the series will be the sum of previous 2 numbers.

Fibonacci series: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, etc

**Program to find Fibonacci Series**

#include <stdio.h> int main() { int i, n, t1 = 0, t2 = 1, nextTerm; printf("Enter the number of terms: "); scanf("%d", &n); printf("Fibonacci Series: "); for (i = 1; i <= n; ++i) { printf("%d, ", t1); nextTerm = t1 + t2; t1 = t2; t2 = nextTerm; } return 0; }

**Output:**

Enter the number of terms: 10 Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34

#### Program To Generate Fibonacci Sequence Up To A Certain Number

#include <stdio.h> int main() { int t1 = 0, t2 = 1, nextTerm = 0, n; printf("Enter a positive number: "); scanf("%d", &n); // displays the first two terms which is always 0 and 1 printf("Fibonacci Series: %d, %d, ", t1, t2); nextTerm = t1 + t2; while(nextTerm <= n) { printf("%d, ",nextTerm); t1 = t2; t2 = nextTerm; nextTerm = t1 + t2; } return 0; }

**Output**

Enter a positive integer: 100 Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89

#### Related C Programs

- C program for prime number
- C program for factorial
- C Program to Compute Quotient and Remainder
- C Program to Find ASCII Value of a Character

Ask your questions and clarify your/others doubts on Fibonacci series by commenting.** Documentation**