Fibonacci Numbers Using Recursion

Demonstration of obtaining Fibonacci
Numbers using a recursive function.

Download it here

Fibonacci Numbers are numbers defined mathematically as
n = n_1 + n_2
where n_1 and n_2 are the two number preceding n in the sequence.
Because the nth number in the sequence is entirely dependent on the
two previous numbers, recursion is an excellent solution for building an algorithm to
provide its user with the numbers in the sequence.

Let's look at some code that solves Fibonacci Numbers using recursion.

#include <iostream>

using namespace std;

//forward declaration (recursive fibonacci algorithm)
int fibonacci(int, unsigned long&);

int main(){
     //local variables
     int input;
     unsigned long temp;

     //get max nth number from user
     cout << "enter a number for n: ";
     cin >> input;

     //call fibonacci numbers to nth number where n is the user input
     if(input > 0){
         for(int i=1; i<=input; i++)
             //print current nth fibonacci number to the screen
             cout << fibonacci(i, temp) << endl;

     //hold screen for user

     return 0;

//fibonacci function
//gets nth fibonacci number using recursion
int fibonacci(int term, unsigned long& n_2){
     unsigned long temp, temp2;

     //if n is greater than 1, use recursion to find nth fiboncacci number
     if(term > 1){
         // n = (n-1) + (n-2)
         temp2 = fibonacci(term-1, n_2);
         temp = n_2;
         n_2 = temp + temp2;
     } else {
         //if n is zero or one (first two numbers in sequence), fibonacci number is 1
         n_2 = 1;
         return 1;

     return temp;