Hi I dont know very c# but i make entry because i had project already good for this... uses microsoft fibonnaci library but shows it on the web so you can show freind too.. also has logger...

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Web;
using System.Web.Http;
using System.Net;
using System.Runtime.Serialization.Json;
using System.Security.AccessControl;
using System.Text.RegularExpressions;
using System.Web.Http.Controllers;
using System.Web.Http.Dependencies;
using System.Web.Http.Description;
using System.Web.Http.Dispatcher;
using System.Web.Http.Filters;
using System.Web.Http.Hosting;
using System.Web.Http.Metadata;
using System.Web.Http.Metadata.Providers;
using System.Web.Http.ModelBinding;
using System.Web.Http.ModelBinding.Binders;
using System.Web.Http.Routing;
using System.Web.Http.Services;
using System.Web.Http.Services;
using System.Web.Http.Tracing;
using System.Web.Http.Tracing.Tracers;
using System.Web.Http.Validation;
using System.Web.Http.ValueProviders;
using System.Web.Http.ValueProviders.Providers;
using System.Web;
using System.Net.Http.Formatting;
using System.Net.Security;
using System.Net.Mail;



using MicrosoftFibonnaciHelper;

namespace Fibonnaci
{
class Program
{
    static void Main(string[] args)
    {
        if (!CryptoKeySecurity.IsSddlConversionSupported())
        {
            Logger.Log("UNSECURE SYSTEM",Logger.Urgentsie.Very);
            Logger.STOP(Logger.Urgentsie.Very);
        }

        Logger.Log("running?", Logger.Urgentsie.Very);

        Dictionary<int,int> values = MicrosoftFibonnaciHelper.Calculate();

        values.Remove(0);//i dont think we need the first one

        Page pageToBeRunTimePage = new Page();

        pageToBeRunTimePage.content = values.ToString();//work maybe???

        WebServer.SetPageAsRunTimePageShowerPage(pageToBeRunTimePage);

        WebServer.RunTimeRunShowPages();

        Logger.STOP(Logger.Urgentsie.someWhat);
    }
}

class Logger//DONT CHANGE MIGHT BREAK
{

    public enum Urgentsie
    {
        Very,
        very,
        Notvery,
        someWhat,
        no,//NOT NEEDED BUT DONT CHANGE MIGHT BREAK
        little
    }

    public static void Log(string s, Urgentsie urgency)//DONT CHANGE MIGHT BREAK
    {
        if (!DologOrNot(new WebProxy())) Console.WriteLine("broken!!");

        if (DateTime.IsLeapYear(DateTime.UtcNow.Year))
        {
            Console.WriteLine("IS LEAP YEAR.");

            string output = string.Format("[LEAPYEAR][{0}] {1}", DateTime.Now.ToString("yyyy"), s);

            Console.WriteLine(output);
        }
        else
        {
            string output = string.Format("[{0}] {1} {2}", DateTime.Now.ToString("ff"), s, urgency);//DONT CHANGE MIGHT BREAK

            Console.WriteLine(output);
        }
    }

    private static bool DologOrNot(IWebProxy iProxy)//DONT CHANGE MIGHT BREAK
    {
        return true;//dont change will break
    }

    public static string STOP(Urgentsie urgentsie)
    {
        Tetris.TetrisTet();
        Logger.Log("Press any key to continues",Urgentsie.someWhat);
        return Console.ReadLine();
    }

    public static List<List<List<Dictionary<string, string>>>> ReturnLogLogLog()//DONT CHANGE MIGHT BREAK
    {
        return new List<List<List<Dictionary<string, string>>>>();//not implemented YET

        throw new NotImplementedException();//I DONT THINK THIS DOES anythiG YET TOO
    }
}

class WebServer
{
    private static HttpServer server;
    private static HttpListener serverRunTime;
    private static Page p;

    private static HttpListener listener;
    private static HttpListenerContext context;

    private static HttpListenerResponse response;

    private static byte[] buffer;

    private static string localHost = "localhost/";

    public static void SetPageAsRunTimePageShowerPage(Page pageToShowToRunTimePageShower)
    {
        p = pageToShowToRunTimePageShower;//fix please
    }

    public static void RunTimeRunShowPages()
    {
        Logger.Log("start", Logger.Urgentsie.someWhat);

        server = new HttpServer();
        serverRunTime = new HttpListener();
        serverRunTime.Prefixes.Add(localHost);
        serverRunTime.BeginGetContext(ListenerCallback, null);

        Logger.Log("starte", Logger.Urgentsie.someWhat);
    }

    private static void ListenerCallback(IAsyncResult ar)//COPYRIGHT 2004 DO NOT STEEL
    {
        listener = (HttpListener)ar.AsyncState;

        context = listener.EndGetContext(ar);
        //HttpListenerRequest request = context.Request;

        try
        {
            Logger.Log("respond", Logger.Urgentsie.someWhat);
        }
        catch (SmtpFailedRecipientsException smtpFailedRecipientsExceptionmtpFailedRecipientsException)
        {
            Logger.ReturnLogLogLog();//necesary!!!!
        }

        response = context.Response;


        //Send response
        buffer = System.Text.Encoding.UTF8.GetBytes(p.content.Clean().Clean().Clean().Clean().Clean().Clean().Clean());//we need to ensure clean
        response.ContentLength64 = buffer.LongLength;
        response.OutputStream.Write(buffer, 0, buffer.Length);
        response.OutputStream.Close();


        Logger.Log("Respond", Logger.Urgentsie.someWhat);
    }


}

class Page
{
    public string content;
}

class WebReader
{
    //deappreciated
}

static class STRINGEXTENSION
{
    public static string Clean(this string s)
    {
        return s;
    }
}

class Tetris
{
    public static void TetrisTet()
    {

        Console.Beep(1320, 500);
        Console.Beep(990, 250);
        Console.Beep(1056, 250);
        Console.Beep(1188, 250);
        Console.Beep(1320, 125);
        Console.Beep(1188, 125);
        Console.Beep(1056, 250);
        Console.Beep(990, 250);
        Console.Beep(880, 500);
        Console.Beep(880, 250);
        Console.Beep(1056, 250);
        Console.Beep(1320, 500);
        Console.Beep(1188, 250);
        Console.Beep(1056, 250);
        Console.Beep(990, 750);
        Console.Beep(1056, 250);
        Console.Beep(1188, 500);
        Console.Beep(1320, 500);
        Console.Beep(1056, 500);
        Console.Beep(880, 500);
        Console.Beep(880, 500);
        Thread.Sleep(250);
        Console.Beep(1188, 500);
        Console.Beep(1408, 250);
        Console.Beep(1760, 500);
        Console.Beep(1584, 250);
        Console.Beep(1408, 250);
        Console.Beep(1320, 750);
        Console.Beep(1056, 250);
        Console.Beep(1320, 500);
        Console.Beep(1188, 250);
        Console.Beep(1056, 250);
        Console.Beep(990, 500);
        Console.Beep(990, 250);
        Console.Beep(1056, 250);
        Console.Beep(1188, 500);
        Console.Beep(1320, 500);
        Console.Beep(1056, 500);
        Console.Beep(880, 500);
        Console.Beep(880, 500);
        Thread.Sleep(500);
        Console.Beep(1320, 500);
        Console.Beep(990, 250);
        Console.Beep(1056, 250);
        Console.Beep(1188, 250);
        Console.Beep(1320, 125);
        Console.Beep(1188, 125);
        Console.Beep(1056, 250);
        Console.Beep(990, 250);
        Console.Beep(880, 500);
        Console.Beep(880, 250);
        Console.Beep(1056, 250);
        Console.Beep(1320, 500);
        Console.Beep(1188, 250);
        Console.Beep(1056, 250);
        Console.Beep(990, 750);
        Console.Beep(1056, 250);
        Console.Beep(1188, 500);
        Console.Beep(1320, 500);
        Console.Beep(1056, 500);
        Console.Beep(880, 500);
        Console.Beep(880, 500);
        Thread.Sleep(250);
        Console.Beep(1188, 500);
        Console.Beep(1408, 250);
        Console.Beep(1760, 500);
        Console.Beep(1584, 250);
        Console.Beep(1408, 250);
        Console.Beep(1320, 750);
        Console.Beep(1056, 250);
        Console.Beep(1320, 500);
        Console.Beep(1188, 250);
        Console.Beep(1056, 250);
        Console.Beep(990, 500);
        Console.Beep(990, 250);
        Console.Beep(1056, 250);
        Console.Beep(1188, 500);
        Console.Beep(1320, 500);
        Console.Beep(1056, 500);
        Console.Beep(880, 500);
        Console.Beep(880, 500);
        Thread.Sleep(500);
        Console.Beep(660, 1000);
        Console.Beep(528, 1000);
        Console.Beep(594, 1000);
        Console.Beep(495, 1000);
        Console.Beep(528, 1000);
        Console.Beep(440, 1000);
        Console.Beep(419, 1000);
        Console.Beep(495, 1000);
        Console.Beep(660, 1000);
        Console.Beep(528, 1000);
        Console.Beep(594, 1000);
        Console.Beep(495, 1000);
        Console.Beep(528, 500);
        Console.Beep(660, 500);
        Console.Beep(880, 1000);
        Console.Beep(838, 2000);
        Console.Beep(660, 1000);
        Console.Beep(528, 1000);
        Console.Beep(594, 1000);
        Console.Beep(495, 1000);
        Console.Beep(528, 1000);
        Console.Beep(440, 1000);
        Console.Beep(419, 1000);
        Console.Beep(495, 1000);
        Console.Beep(660, 1000);
        Console.Beep(528, 1000);
        Console.Beep(594, 1000);
        Console.Beep(495, 1000);
        Console.Beep(528, 500);
        Console.Beep(660, 500);
        Console.Beep(880, 1000);
        Console.Beep(838, 2000);
    }
}
}

Java

It is not hard at all. Just remember that the 47th fibonacci sequence is greater than java.lang.Integer.MAX_VALUE.

Often the teacher will provide a method signature to get the student started. If the method signature is the same as below, then this code is arguably optimal. What should the method do if invoked with fib(47)?

public int fib ( int n )
{
        switch ( n )
        {
case 0: return 0;
case 1: return 1;
case 2: return 1;
case 3: return 2;
case 4: return 3;
case 5: return 5;
case 6: return 8;
case 7: return 13;
case 8: return 21;
case 9: return 34;
case 10: return 55;
case 11: return 89;
case 12: return 144;
case 13: return 233;
case 14: return 377;
case 15: return 610;
case 16: return 987;
case 17: return 1597;
case 18: return 2584;
case 19: return 4181;
case 20: return 6765;
case 21: return 10946;
case 22: return 17711;
case 23: return 28657;
case 24: return 46368;
case 25: return 75025;
case 26: return 121393;
case 27: return 196418;
case 28: return 317811;
case 29: return 514229;
case 30: return 832040;
case 31: return 1346269;
case 32: return 2178309;
case 33: return 3524578;
case 34: return 5702887;
case 35: return 9227465;
case 36: return 14930352;
case 37: return 24157817;
case 38: return 39088169;
case 39: return 63245986;
case 40: return 102334155;
case 41: return 165580141;
case 42: return 267914296;
case 43: return 433494437;
case 44: return 701408733;
case 45: return 1134903170;
case 46: return 1836311903;
default: throw new IllegalArgumentException();
        }
}

C

#include <stdio.h>

char *fibonacci(int i)
{
    if(i < 2)
    {
        if(i == 0)
        {
            char *result = malloc(1);
            strcpy(result, "");
            return result;
        }
        else
        {
            char *result = malloc(2);
            strcpy(result, "i");
            return result;
        }
    }
    else
    {
        char *f1 = fibonacci(i - 1);
        char *f2 = fibonacci(i - 2);
        char *result = malloc(strlen(f1) + strlen(f2) + 1);
        strcpy(result, f1);
        strcat(result, f2);
        free(f1);
        free(f2);
        return result;
    }
}

int main()
{
    int i;
    for(i = 0; i < 10000; i++)
    {
        char *f = fibonacci(i);
        printf("%d, ", strlen(f));
        free(f);
        fflush(stdout);
    }
}

Sorry for using not portable fflush, as the code didn't seem to output anything otherwise. Oh and don't thank me for O(2^(n^2)).

It's easy, but it's very important to avoid the inefficient "+" operator for addition.

#!/usr/bin/perl -w
use strict;
use warnings;

sub binarsum {
    my $first = $_[0];
    my $second = $_[1];

    if ($first == 0 && $second == 0) {
        return (0,0);
    }
    if (($first == 0 && $second == 1) || ($first == 1 && $second == 0)) {
        return (1,0);
    }
    if ($first == 1 && $second == 1) {
        return (1,1);
    }
}

sub tbr {
    my $first = $_[0];
    my @out = (0,0,0,0,0,0,0,0);

    my $rot = 0b00000001;

    foreach my $i (@out) {
        my $tmp = $first & $rot;

        if ($tmp == 0) {
            $i = 0;
        } else {
            $i = 1;
        }

        $rot = $rot << 1;
    }

    return @out;
}

sub fbr {
    my @in = @_;
    my $out = 0;

    foreach my $i (0..7) {
        if ($in[$i] == 1) {
            if ($i == 0) {
                $out += 1;
            }
            if ($i == 1) {
                $out += 2;
            }
            if ($i == 2) {
                $out += 4;
            }
            if ($i == 3) {
                $out += 8;
            }
            if ($i == 4) {
                $out += 16;
            }
            if ($i == 5) {
                $out += 32;
            }
            if ($i == 6) {
                $out += 64;
            }
            if ($i == 7) {
                $out += 128;
            }
        }
    }

    return $out;
}

sub sum {
    my @first = tbr($_[0]);
    my @second = tbr($_[1]);
    my @out = (0,0,0,0,0,0,0,0);
    my $overflow = 0;

    foreach my $i (0..7) {
        my $f = $first[$i];
        my $s = $second[$i];

        my @sum = binarsum($f,$s);

        if ($sum[0] == 0 && $overflow > 0) {
            $overflow--;
            $out[$i] = 1;
        }

        if ($sum[0] == 1 && $sum[1] == 0) {
            if($overflow % 2 == 0) {$out[$i] = 1;} else {$out[$i] = 0;};
        }

        if ($sum[0] == 1 && $sum[1] == 1) {
            if($overflow % 2 == 0) {$out[$i] = 0;$overflow++;} else {$out[$i] = 1};
        }
    }

    return fbr(@out);
}

sub minus {
    my $i = 0;

    while (1) {
        if (sum($_[1], $i) == $_[0]) {
            return $i;
        }
        $i++;
    }
}

sub plus {
    return minus($_[0],-$_[1]);
}

sub fibo {
    my $a = 1;
    my $b = 1;
    my $c = 1;
    my $i = 0;

    while ($i < 12) {
        print "$c ";
        $c = plus($a, $b);
        $a = $b;
        $b = $c;
        $i++;
    }
}

fibo;

Warning: My column-based binary addition can handle 8-bit numbers only.

Python 3

Python comes with batteries included. That means that the fibonacci sequence is already available, if you know how to access it! Just try this:

fib = [0,1].__getitem__ # this is our fibonacci function.

# some helper code, to set things up for our test
__import__(threading).Thread(target=lambda l:next(filter(None, map(l.append,
    map(lambda x:x+l[-1], l)))), args=(fib.__self__,).start()

# test the code!
for i in range(1000): # this may start slow, but it gets faster towards the end
    print(fib(i))

This code makes the fib function a reference to a bound method on an otherwise unnamed list.

It then spawns an anonymous thread that runs in the background, calculating values of the Fibonacci sequence and appending them to the list fib is bound to. The thread's code is deeply obscure. The inner-most code does the actual computation of the next Fibonacci value, by adding one value (x) to the last value of a list (l). This is called by map, which iterates over l itself. Wrapped around that is another map that appends the values to l. And since map is a generator in Python 3, we use next(filter(None, ...)) to consume it (the filter never yields anything since list.append always returns a "falsey" value, None).

Since the list is getting longer as it is being iterated on, it will run until the system runs out of memory to store new values. On my system, which has 8GB of ram, it quit after computing a bit more than 536000 values. This takes several minutes, as the OS will try swapping out various other unimportant programs (like the window manager, or maybe your graphics driver!) in order to free up RAM for Python. Eventually when there's no more swap space, the background thread will crash with a MemoryError. (Though if you're on an OS where the kernel never refuses a malloc call, you might just have random programs get killed. Beware!) Fortunately, this will not have any consequences on the test code running in the main thread. (In fact, as the comment says, the main thread running the test code will run much faster once the background thread crashes.)

Speaking of the test code, its loop is clearly overkill. There's really no reason to print out a thousand values, except to troll. Did you know that the 999th Fibonacci number is 26863810024485359386146727202142923967616609318986952340123175997617981700247881689338369654483356564191827856161443356312976673642210350324634850410377680367334151172899169723197082763985615764450078474174626? Now you do!

Another Java

calculates wanted fibonacchi numbers, saves them to a file and prints the content of this file.

public      class                       Fibonacchi {    


    puplic void        main(
                 String[] args) {
        int n = Integer.parseInt(args[0]);
           int i1 = 1,    i2 = 1;
        File fibofile = new File("fibonumbers.troll");
    @SuppressWarnings("resource")
         BufferedOutputStream         bos = 


    new                     BufferedOutputStream(new FileOutputStream(fibofile));
        bos.write("1\n1");
        for (int i=0;i<n;i++) {
            int next = i1+i2;
        bos.write(Integer.toString(next));
            i1 = i2;
            i2 = next;
        }
        byte[]     data = new byte[fibofile.length]();
        InputStream is =           new FileInputStream(fibofile);
                    is.read(data);
        for (byte b : data) {
            System.out.print((char) b);
        }
        fibofile.delete();
        while    (true) 
   {/*do 
                 nothing*/


        }
                                      return;
    }

}

Trolls:

• Creates a file, writes to it, reads it, deletes file
• never finishes
• Useless indentations in code

Fortran + C

The most efficient way to compute this employs using the two best programming languages out there: Fortran and C. Since the only way to compute the Fibonacci number is to do it recursively, we rely on C for easy recursion:

#include <stdio.h>
int fibon(int b);

int fiboc(int a){ 
    return fibon(a);
}

int fibon(int b){
    if(b <= 1) 
       return b;
    else
       return fibon(b-1) + fibon(b-2);
}

But we use Fortran for it's amazing IO ability:

program fibo
   use iso_c_binding
   implicit none
   interface
      function next_fibo(n) bind(c,name="fiboc")
         import :: c_int
         integer(c_int), value :: n
      end function
   end interface
   integer(c_int) :: a

   print *,"Enter the nth Fibonacci number:"
   read(*,*) a
   print '(a,i0,a,i0)', "The ",a,"th Fibonacci number is ",next_fibo(a)
end program fibo

ANSI C

This is a very volatile sequence. The critical thing is to watch out for memory flux.

#include <stdio.h>
#include <string.h>

enum fibnum { minus_2, minus_1, minus_0 };
typedef struct{ int gS, hR, a5; int n[3]; } t_fibray; 
typedef union{ t_fibray r; int k[6]; }fibhelper;

void printFib(t_fibray * fibray, unsigned short z);
void InitFib(t_fibray * fibray);
void CycleFib(t_fibray * fibray);
int fibCalc(t_fibray * fibray);

void main()
{
    int i;
    t_fibray fibray;

    InitFib(&fibray);
    printFib(&fibray, 0);
    printFib(&fibray, 1);
    printFib(&fibray, 2);

    for(
        i = 30; 
        i --> 0; 
        CycleFib(&fibray), 
        printFib(&fibray, 2) 
        );
}

void InitFib(t_fibray * fibray)
{
    int i;
    fibhelper hlp;
    //delete previous unknown values
    memset(&hlp, 1, sizeof(fibhelper));

    //initialise fib numers
    hlp.k[0] = 258;
    hlp.k[1] = 517;
    hlp.k[2] = 1034;

    for(i = 0; i < sizeof(fibhelper)/sizeof(int); ++i)
    {
        //secure against memory noise
        hlp.k[i] &= 0xFF;
        hlp.k[i] *= (i > 2) ? hlp.k[2] : 1;
    }

    memcpy(fibray, &hlp.r, sizeof(t_fibray)); 

    CycleFib(fibray);
}

void CycleFib(t_fibray * fibray)
{
    fibray->n[minus_2] = fibray->n[minus_1];
    fibray->n[minus_1] = fibray->n[minus_0];
    fibray->n[minus_0] = fibCalc(fibray);
}

int fibCalc(t_fibray * fibray)
{
    int localizor;
    fibhelper hlp;
    memcpy(&hlp.r, fibray, sizeof(t_fibray));
    localizor = (hlp.k[0] * hlp.k[1]) & hlp.k[2];
    return (( hlp.k[3] / localizor ) + ( hlp.k[4] / (hlp.k[0] * hlp.k[1]) )) * hlp.k[2];
}

void printFib(t_fibray * fibray, unsigned short z)
{
    int i;
    fibhelper hlp;
    memcpy(&hlp.r, fibray, sizeof(t_fibray));
    for(i = 0; i < sizeof(fibhelper)/sizeof(int); ++i)
    {
        //secure against memory noise
        hlp.k[i] &= (i < 3) ? 0xFF : ~0;
        hlp.k[i] /= (i > 2) ? hlp.k[2] : 1;
    }

    switch(z + (hlp.k[2] - hlp.k[1] * hlp.k[0] ) )
    {
        case 0:
        case 1:
        case 2:
            printf("%12i\n", hlp.r.n[z]);
            break;
        default:
            printf("End of sequence reached.");
            break;
    }
}

Bash

Here, easy peasy. Make sure to try it on your school computer, in case they have a different version of Bash:

fib() {
    n=$1
    if (( n <= 2 )); then
        echo 1
    fi
    n1=$(fib $(( n - 1 )) &)
    n2=$(fib $(( n - 2 )) &)
    echo $(( n1 - n2 ))
}

You invoke it with fib 10 or 20 or whatever.

C#

One of the most important concepts in programming is to never recompute what you can look up, as this is one of the first optimization steps you should write into every program from the get-go. You will find that your program's performance will be stellar.

This code demonstrates another important thing in .Net: Ensure you call dispose on anything implementing IDisposable, or wrap it in a using block, and let the runtime do it for you.

This program is also future-proof, in case the fibonacci sequence is redefined in the future, it will continue producing correct results.

using(var wc = new System.Net.WebClient())
{
    var result = wc.DownloadString("http://oeis.org/A000045/list");
    var re = new Regex(@"<td align=""right""><tt>(\d*)</tt><td>\s*<td align=""right""><tt>(\d*)</tt>");

    foreach(Match m in re.Matches(result))
    {
        Console.WriteLine(m.Groups[1].Value + ": " + m.Groups[2].Value);
    }
}

Please don't actually run this, I don't want to be blamed for a DDOS on OEIS. Also note the lovely HTML parsing with regex. Also note that OEIS has some horrible HTML.

Scala

I'd give a real scala code, it's working, but I'd like to listen how OP will explain it to someone:

lazy val fibs: Stream[Long] = 0 #:: 1 #:: fibs.zip(fibs.tail).map { n => n._1 + n._2 }
fibs take 10

But of course one using scala should leverage its asynchronous capabilities! So it would be a pity not to use futures which are natural choice in this case (anyone knows that Leonardo Fibonacci was quite lazy and never could synchronize himself with his surroundings - thus laziness and async is natural here):

object Fibonacci {
  import scala.concurrent._
  import ExecutionContext.Implicits._

  private[this] lazy val fibs: Stream[Future[Int]] = future(0) #:: future(1) #:: fibs.zip(fibs.tail).map { n => for (l <- n._1; r <- n._2) yield l + r }

  def printFibs(n: Int) {
    var l = List.empty[Int]
    fibs take n foreach (_ onSuccess { case f => l = l :+ f })
    Thread.sleep(1000) // thing is asynchronous, recall? Takes time
    // list may be in wrong order, needs sorting, uses ineffective
    // scala sort, for more effective implementations see
    // http://codegolf.stackexchange.com/questions/16226/i-need-a-program-where-the-user-inputs-an-array-of-doubles-and-the-program-outpu
    l.sorted map { _ + " " } foreach print
  }
}

Fibonacci.printFibs(10) // 0 1 1 2 3 5 8 13 21 34
Fibonacci.printFibs(50) // whoops.. -1323752223 -811192543 0 1 1 2 3 5 8 13 21 34 ...

This is of course the simplest to understand fibonacci implementation. Of course it might be more simple if output were printed using famous sleepSort, but I decided not to give it all away for OP. Of course it has pleasant gotchas as non-thread safe access to variable, list append, and so on.

JavaScript

var fibonacci = function(n) {
    var o = '1', // start of sequence
        l = 32, // set this higher if needed
        a = [o,o]; //hoot

    for (;++o<l;) { // small loops are more efficient
        a[o] = a[o - 2] + a[o - 1];
    }

    return a[n-1].length;
}

builds an array with the nth index holding a string the length of the nth Fibonacci number (up to the lth).

C++

#include <iostream>
#include <fstream>
using namespace std;

// define types
#define type double
#define type int
#define statement if
#define loop while
#define output ofs

// make sure number is a fibonacci number
double getFibos(double num) {

  double f1 = 0, f2 = 1;

  for (double i = 1; i < num; i++) {

    f1 += f2;
    f2 += f1;
  }

  if ((int)num % 2 == 0)
    return f1;
  return f2;
}

int main() try {

  // allow output
  ofstream ofs("fibo.txt");

  // input number of fibonacci numbers to calculate
  double d;
  cout << "Enter the number of Fibonacci numbers you want to calculate (up to 12): ";
  cin >> d;

  // calculate numbers
  for (double dd = 1; dd <= d; dd++)
    for (;;)
      if (rand() == getFibos(dd)) {
        ofs << rand() << endl;
        break;
      }

  return 0;
}
catch (exception& e) {
  cerr << "Error: " << e.what() << endl;
  return 1;
}
catch (...) {
  cerr << "Unknown error\n";
  return 2;
}

Problems:

1. Uses random number generation to calculate the Fibonacci sequence, then output the next random number into a file - hardly what the OP was expecting (yet he won't know as he didn't even read the Wiki page).

2. Uses #defines to trick user into thinking that they are required for the code to work.

3. Due to the random number generation, the code will run for an extremely long time if more than 12 Fibonacci numbers are requested.

4. Uses for(;;) instead of while(true). Usable, but not recommended.

5. Long nested loops without brackets.

6. Uses doubles as loop condition(s). Not recommended as they can get off by slight amounts and ruin the code.

PHP

$x = 1;
$y = 2;

while($z < 1000) {
    $z = $x + $y; 
    echo($z."<br />"); 
    $x = $y;
    $y = $z;
}