In this tutorial, we will learn how to write a **C Program to display fibonacci series**. The Fibonacci series is a sequence of numbers in which each number is the sum of the two previous numbers, usually starting with 0 and 1. We will see two different ways to accomplish this:

## Example 1: C Program to print Fibonacci Series using loop

In this program, we are using a for loop to print fibonacci series.

#include <stdio.h>

int main() {

int n, first_term = 0, second_term = 1, next_term, i;

// Ask user to input number of terms

printf("Enter the number of terms: ");

scanf("%d", &n);

printf("First %d terms of the Fibonacci series:\n", n);

for (i = 0; i < n; i++) {

if (i <= 1) {

next_term = i;

} else {

next_term = first_term + second_term;

first_term = second_term;

second_term = next_term;

}

printf("%d ", next_term);

}

printf("\n");

return 0;

}

### Output:

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

## Example 2: C Program to display Fibonacci series using recursion

In this program, we are using a recursive function `fibonacci_series(n)`

. This function calls itself to determine the nth term. For example, if `fibonacci_series(3)`

is called, it calls itself to determine 3rd term,` fibonacci_series(2) + fibonacci_series(1)`

.

Let’s see the complete code, it prompts user to enter the number of terms and then it calls the recursive function in a loop to print series upto entered term.

#include<stdio.h> // Function to calculate the nth Fibonacci number int fibonacci_series(int); int main() { int count, i; printf("Enter number of terms:"); scanf("%d", &count); printf("\nFibonacci series:\n"); for (i = 0; i < count; i++) { // Print the ith Fibonacci number printf("%d\n", fibonacci_series(i)); } return 0; } // Recursive function to calculate the nth Fibonacci number int fibonacci_series(int num) { if (num <= 1) return num; else // Calculate the nth Fibonacci number recursively return (fibonacci_series(num - 1) + fibonacci_series(num - 2)); }

### Output:

Enter number of terms: 6

Fibonacci series:

0

1

1

2

3

5

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