Quote:

Uhh... i did not say that switch to C. C++ is similar enough with C# and whatever they say ... C++ does calculations about 5 times quicker than C#.

   double d1 = 0.727272;
   double d2 = 0.26252;
   double d3 = 343432.232;

   for (int i = 0; i < 100000000; i++)
   {

      d3 = d1 * d2;
      d1 = d3 * d2;
      d2 = d2 * d2;
      d3 = d1 * d2;
      d3 = d3 * d2;
   }

using System;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            DateTime time1 = DateTime.Now;
            double d1 = 0.727272;
            double d2 = 0.26252;
            double d3 = 343432.232;

            for (int i = 0; i < 100000000; i++)
            {

                d3 = d1 * d2;
                d1 = d3 * d2;
                d2 = d2 * d2;
                d3 = d1 * d2;
                d3 = d3 * d2;
            }
            DateTime time2 = DateTime.Now;

            TimeSpan span = time2 - time1;
            
            Console.WriteLine("{0};{1};{2};{3}",span, d1,d2,d3);
        }
    }
}

#include "stdafx.h"
#include <sys/timeb.h>
#include <sys/types.h>
#include <iostream>

int _tmain(int argc, _TCHAR* argv[])
{

    timeb time1;
    ftime(&time1);
    double d1 = 0.727272;
    double d2 = 0.26252;
    double d3 = 343432.232;

    for (int i = 0; i < 100000000; i++)
    {

        d3 = d1 * d2;
        d1 = d3 * d2;
        d2 = d2 * d2;
        d3 = d1 * d2;
        d3 = d3 * d2;
    }
    timeb time2;
    ftime(&time2);
 
    std::cout << (time2.time - time1.time)*1000 + time2.millitm - time1.millitm 
        << ";" << d1 << ";" << d2 << ";" << d3 << "\n";
    char c;
    std::cin >> c;
    
    return 0;
}

Kotk wrote on Fri, 09 February 2007 15:42

C++ compilers tend to optimize the code like you posted entirely out so i somewhat modified it to give any usage to the variables there... and also to measure the time directly in code. Somehow i get here different results than you. Maybe i just know C# not well enough and do something wrong with it. Other possibilities are that you run not "C++" but "managed C++" or that you run "Debug" version of C++. On that case your computer seems about 4 times better than mine.

         Console.WriteLine("{0};{1};{2};{3}", span, d1, d2, d3);