Program for Fibonacci numbers

The Fibonacci numbers are the numbers in the following integer sequence.

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, ……..

In mathematical terms, the sequence Fn of Fibonacci numbers is defined by the recurrence relation

    Fn = Fn-1 + Fn-2

with seed values

   F0 = 0 and F1 = 1.

Given a number n, print n-th Fibonacci Number.
Examples:

Input  : n = 2
Output : 1

Input  : n = 9
Output : 34

Recommended: Please solve it on “PRACTICE ” first, before moving on to the solution.

Write a function int fib(int n) that returns Fn. For example, if n = 0, then fib() should return 0. If n = 1, then it should return 1. For n > 1, it should return Fn-1 + Fn-2

For n = 9
Output:34

Following are different methods to get the nth Fibonacci number.

Method 1 ( Use recursion )
A simple method that is a direct recursive implementation mathematical recurrence relation given above.

• C++
• C
• Java
• Python
• C#
• PHP

//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; }

Output

34