Here I am going to discuss about Fibonacci Series in Recursion form.

Means,

How **Fibonacci Recursion** Work?

First gone through,

**What is recursion?**

A recursion is a function which calls itself and keeps on repeating until the condition is satisfied for the termination of the process.

**Syntax:**

void recur() { recur(); } int main() { recur(); }

**What is a Fibonacci series?**

A Fibonacci is a series of number which is represented as:

0,1,1,2,3,5,8,13,21,34…..

It is generated by adding the present number with its number at the previous place.

0,1 : 0+1=1 0,1,1 : 1+1=2 0,1,1,2 : 2+1=3 0,1,1,2,3 : 3+2=5 0,1,1,2,3,5 : 5+3=8 and so on

This is how a Fibonacci series is generated. We will see how this series can be generated and its working using recursion in this article.

**Explanation:**

- We will take an integer i for a loop where the loop will work from 0 to n i.e., to the number of series desired by the user and the loop gets incremented by 1.
- Inside the loop it will be printing the value on calling the function fibo which will return the series.
- In the function fibo if the value of i which is called with the function tends to be 0 then it will return the value 0 which gets printed and then if the value tends to be 1 then it will return the value 1.
- Moreover in the function a recursion process is called as

`fibo(i-1)+fibo(i-2)`

which states that the resultant value of i-1 and i-2 is added where the function for i-1 runs separately and the function for i-2 runs separately and in the end the result of both the functions are added and returned.

- Printf function prints the value of the content returned from the fibo function.
- When the value of i reaches equal to or greater than n then the loop gets terminated.

Implementation of above steps:

#include<stdio.h> int fibo(int i) { if(i==0) return 0; if(i==1) return 1; return (fibo(i-1)+fibo(i-2)); } int main() { int i,n; printf("\nEnter the series of fibonacci required"); scanf("%d",&n); for (i=0;i<n;i++) printf("%d\t",fibo(i)); return 0; }

**Output:**

The above program and explanation show how a Fibonacci series works using recursion. There may be different logics among which the above shown is a type.

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