#include <iostream>
#include <ctime>
#include <stdio.h>
#include <time.h>
 
using namespace std ;
 
unsigned long first = 0;
unsigned long second = 1 ;
unsigned long result ;
 
time_t start, end ;
double total ;
 
int x ;
int ans ;
 
unsigned long fib( int n ) ;
 
int main()
{
	cout << endl << " Fibonacci Sequence Test -> C++ " << endl ;
	cout << "_____________________________________" << endl ;
 
 
	cout << endl << endl << endl ;
 
	cout << "Number of iterations to calculate:  " ;
	cin >> x ;
	cout << endl << endl ;
 
	cout << "1.  Iterative" << endl ;
	cout << "2.  Recursive" << endl ;
	cout << "Select method:  " << endl ;
	cin >> ans ;
	cout << endl ;
 
	if ( ans == 1 )
	{
		start = clock() ;
		for ( int i = 0; i <= x ; i++ )
		{
			//cout << result << endl ;
			first = second ;
			second = result ;
			result = first + second ;
		}
		end = clock() ;
		total = (end - start) * .001 ;
 
		cout << "Result:  " << endl ;
		cout.precision(10) ;
		cout << "Total Time:  " << total << endl ;
	}
	else if ( ans == 2 )
	{
		start = clock() ;
		result = fib(x) ;
		end = clock() ;
		total = (end - start) * .001 ;
 
		cout << "Result:  " << result << endl ;
		cout.precision(10) ;
		cout << "Total Time:  " << total << endl ;
	}
 
 
	return 0 ;
}
 
unsigned long fib( int n )
{
	    if (n <= 1)
			return n;
		else
			return fib(n-1)+fib(n-2);
};

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
 
namespace FibCsharp
{
 
    public partial class Form1 : Form
    {
        double startTime;
        double endTime;
        double totalTime;
 
        ulong first = 0;
        ulong second = 1;
        ulong result;
 
        public Form1()
        {
            InitializeComponent();
        }
 
        private void button1_Click(object sender, EventArgs e)
        {
            startTime = DateTime.Now.Hour * 3600 + DateTime.Now.Minute * 60 + DateTime.Now.Second + DateTime.Now.Millisecond * .001;
            for (int i = 1; i <= 40; i++)
            {
                first = second;
                second = result;
                result = first + second;
            }
            endTime = DateTime.Now.Hour * 3600 + DateTime.Now.Minute * 60 + DateTime.Now.Second + DateTime.Now.Millisecond * .001;
            totalTime = endTime - startTime;
 
            label1.Text = Convert.ToDouble((totalTime)).ToString();
            textBox1.Text = result.ToString();
 
 
        }
 
        private void button2_Click(object sender, EventArgs e)
        {
            startTime = DateTime.Now.Hour * 3600 + DateTime.Now.Minute * 60 + DateTime.Now.Second + DateTime.Now.Millisecond * .001;
            result = fib(40);
            endTime = DateTime.Now.Hour * 3600 + DateTime.Now.Minute * 60 + DateTime.Now.Second + DateTime.Now.Millisecond * .001;
            totalTime = (endTime - startTime);
 
            label1.Text = Convert.ToDouble(totalTime).ToString();
            textBox1.Text = result.ToString();
        }
 
        private ulong fib(ulong n)
        {
            if (n <= 1)
                return n;
            else
                return fib(n - 1) + fib(n - 2);
        }
    }
}

 Fibonacci Sequence Test -> C++
_____________________________________
 
 
 
Number of iterations to calculate: 40
 
 
1. Iterative
2. Recursive
Select method:
2
 
Result: 102334155
Total Time: 2.5
Press any key to continue . . .

 Fibonacci Sequence Test -> C++
_____________________________________
 
 
 
Number of iterations to calculate: 40
 
 
1. Iterative
2. Recursive
Select method:
2
 
Result: 102334155
Total Time: 2.391
Press any key to continue . . .

Best Result for C#3 and .Net3.5 was 3.562