Re: Java vs C++ speed (IO & Sorting)

Razii <>
Sat, 22 Mar 2008 04:32:54 -0500
On Fri, 21 Mar 2008 08:26:09 -0700 (PDT), wrote:

Im not sure if i used the right optimization flags to compile the java
program so if its wrong please tell me how i should compile it, since
i expected to obtain similar results.

Try these verions (only IO test) with g++ (in this version java is
using nio package for reading and writing).

Let me know what time you get for Java and c++ with g++

=== java ===
import java.nio.*;
import java.nio.channels.*;

public class CopyFile
    public static void main(String[] arg) throws Exception
  FileChannel in = new FileInputStream("bible.txt").getChannel();
  FileChannel out = new FileOutputStream("output.txt").getChannel();

            long start = System.currentTimeMillis();
    in.transferTo (0, in.size(), out);
    out.close(); in.close();
    long end = System.currentTimeMillis();

       System.out.println("Time for reading and writing files: " +
(end - start) + " ms");

===== C++ Version =======
#include <ctime>
#include <fstream>
#include <iostream>
int main(int argc,char *argv[])
   std::ifstream src("bible.txt");
   std::ofstream dst("output.txt");
   clock_t start=clock();
   dst << src.rdbuf();
   clock_t endt=clock();

    std::cout <<"Time for reading and writing file: " <<
       double(endt-start)/CLOCKS_PER_SEC * 1000 << " ms\n";
    return 0;

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