# How to write fibonacci Series program in C

**Here is Fibonacci Series program in C.**

// Fibonacci Series using Recursion

#include <stdio.h>

int fib(int n)

{

if (n <= 1)

return n;

return fib(n – 1) + fib(n – 2);

}

int main()

{

int n = 9;

printf(“%d”, fib(n));

getchar();

return 0;

}

## Fibonacci Series in C without recursion

#include<stdio.h>

int main()

{

int n1=0,n2=1,n3,i,number;

printf(“Enter the number of elements:”);

scanf(“%d”,&number);

printf(“\n%d %d”,n1,n2);//printing 0 and 1

for(i=2;i<number;++i)//loop starts from 2 because 0 and 1 are already printed

{

n3=n1+n2;

printf(” %d”,n3);

n1=n2;

n2=n3;

}

return 0;

}

## Fibonacci Series using recursion in C

#include<stdio.h>

void printFibonacci(int n){

static int n1=0,n2=1,n3;

if(n>0){

n3 = n1 + n2;

n1 = n2;

n2 = n3;

printf(“%d “,n3);

printFibonacci(n-1);

}

}

int main(){

int n;

printf(“Enter the number of elements: “);

scanf(“%d”,&n);

printf(“Fibonacci Series: “);

printf(“%d %d “,0,1);

printFibonacci(n-2);//n-2 because 2 numbers are already printed

return 0;

}

**Fibonacci**Sequence is the

**series**of

**numbers**: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, … The next

**number**is found by adding up the two

**numbers**before it.

…

**Fibonacci Sequence**

- The 2 is found by adding the two numbers before it (1+1)
- The 3 is found by adding the two numbers before it (1+2),
- And the 5 is (2+3),
- and so on!

## Fibonacci Series up to n terms

`#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;`

}

Satya Prakash`

Formulla for fibonacci series is:

a

_{n}= [ Phi^{n}– (phi)^{n}]/Sqrt[5]. where Phi=(1+Sqrt[5])/2 is the so-called golden mean, and phi=(1-Sqrt[5])/2 is an associated golden number, also equal to (-1/Phi).This

formulais attributed to Binet in 1843, though known by Euler before him.Related