Home » Blog » C Program to find fibonacci series

# C Program to find fibonacci series ## 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

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