Private Function Fibonacci(ByVal n As Long) As Long
Dim n1 As Long
Dim n2 As Long
Dim i As Long
    If n > 0 Then
        If n <= 2 Then
            Fibonacci = 1
        Else
            n1 = 1
            n2 = 1
            For i = 3 To n - 1
                If i And 1 Then
                    n1 = n1 + n2
                Else
                    n2 = n1 + n2
                End If
            Next i
            Fibonacci = n1 + n2
        End If
    End If
End Function

// Renvoie le énième terme de la suite de Fibonacci
private static long Fibonnaci(int term) 
{
   long n1 = 1; 
   long n2 = 1;

   if (term > 0) 
   {
      if (term <= 2) return 1; 
      else
      {
         for (int i = 3; i < term; i++) 
         {
             if ((i & 1) == 0) n1 += n2;           
             else n2 += n1; 
         }
         return n1 + n2; 
      }
   }
   return -1; 
}

function Fibbonacci(level)
{
if(level)
{
var n1=1;
var n2=1;
var n3=0;
var tab=[1,1]
for(i=0;i<level;i++)
{
n3=n1+n2;
n1=n2;
n2=n3;
tab.push(n3)
}
this.array=tab
this.number=tab*Math.pow(10,-(tab.length-1));
}
else
{
return false;
this.number=null;
this.array=null;
}
}
var suite_de_fibbonacci=new Fibbonacci(18);
var tableau_de_valeur=suite_de_fibbonacci.array;
var nombre_de_fibbonnacci=suite_de_fibbonnaci.number;

(* Récursive terminale. Exemple d'utilisation : fibonacci 10 donne 55 *)
let fibonacci = function
    | n when n <= 2 -> 1
    | n -> let rec loop (x, y) = function
        | i when i = n -> x + y
        | i when i land 1 = 1 -> loop (x + y, y) (i + 1)
        | i -> loop (x, x + y) (i + 1)
    in loop (1, 1) 3
     

#include <iostream>
template <int N> inline int fibo(){
    return fibo<N-1>()+fibo<N-2>();
};
template <> inline int fibo<1>(){
    return 1;
};
template <> inline int fibo<0>(){
    return 1;
};

int main(){
    //inconvéniant : la récurence exige qu'on le fasse de 500 en 500, sinon, G++ n'aime pas...
    int a=fibo<4>();
    std::cout << a << "\n";
    return 0;
}

#include <stdio.h>
unsigned long fib(unsigned long n)
{
  return (n < 2) ? 1 : fib(n-2) + fib(n-1);
}
int main()
{
  int n=30;
  printf("fib(%ld)=%ld\n", n, fib(n));
  return 0;
}

use strict;
sub Fib
{
  my ($n) = @_;
  return 1 if $n < 2;
  return Fib($n - 2) + Fib($n - 1);
}
my $n = 30;
printf "Fib(%.0f)=%.0f\n",$n, Fib($n),;

<?php
function fib($n){
   if($n < 2) { return 1; }
   else { return fib($n - 2) + fib($n - 1); }
}
$n = 30;
printf("Fib(%.0f)=%.0f\n", $n, fib($n));
?>

#!/usr/env/python
def Fib(n):
    if n < 2: return 1
    return Fib(n-2) + Fib(n-1)
n = 30
print "Fib(%.0f)=%.0f" % (n, Fib(n))

public class fibo {
    public static void main(String args[]) {
      int N = 30; //Integer.parseInt(args[0]);
      System.out.println("fib("+ N + ")=" + fib(N));
    }
    public static int fib(int n) {
      if (n < 2) return(1);
      return ( fib(n-2) + fib(n-1) );
    }
}

#include <stdio.h>
#include <math.h>
double fib(unsigned long n)
{
    // On va s'aide du nombre d'or
    return floor(pow((1 + sqrt(5)) / 2, (double)n) / sqrt(5)); // on arrondi
}
int main(void)
{
    double r = fib(71);
    printf("%lf\n", r);
    return 0;
}

long Fibonacci(long Rank)
{
long n1,n2;
  if (Rank==0)
    return 0;
  if (Rank<=2)
    return 1;

  Rank-=3;
  n2 = 1;

  if (Rank & 1) {
    n1 = 2; 
    Rank--;
  }

  do {
    n2 = n1 + n2;
    n1 = n1 + n2; 
  } while(Rank-=2)
  
  return n1+n2;
}