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

From:

Razii <DONTwhatevere3e@hotmail.com>

Newsgroups:

comp.lang.c++,comp.lang.java.programmer

Date:

Thu, 20 Mar 2008 10:29:26 -0500

Message-ID:

<s905u3l6qro5q40l1lt9bntv46eaivud4n@4ax.com>

On Thu, 20 Mar 2008 08:41:51 -0600, Jerry Coffin <jcoffin@taeus.com>
wrote:

#include <fstream>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <ctime>
#include <iterator>
#include <set>

// the main modification is here
#ifdef CSTDIO
   #include "cstdio.h"
   namespace s = JVC;
#else
   namespace s = std;
#endif

// I've also gotten rid of the "using namespace std;" and explicitly
// qualified the names below.
//

int main() {

   typedef std::multiset<std::string> mss;
   mss buf;
   std::string linBuf;

   s::ifstream inFile("bible.txt");

   clock_t start=clock();

   while(s::getline(inFile,linBuf)) buf.insert(buf.end(), linBuf)
       ;

   s::ofstream outFile("output.txt");

   std::copy(buf.begin(),buf.end(),
       s::ostream_iterator<std::string>(outFile,"\n"));

   clock_t endt=clock();
   std::cout <<"Time for reading, sorting, writing: " <<
      double(endt-start)/CLOCKS_PER_SEC * 1000 << " ms\n";
   return 0;
}

Cut and pasted above to IOSort.cpp. Didn't do anything...

C:\>cl IOSort.cpp /O2
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 15.00.21022.08
for 80x86
Copyright (C) Microsoft Corporation. All rights reserved.

IOSort.cpp
C:\Program Files\Microsoft Visual Studio 9.0\VC\INCLUDE\xlocale(342) :
warning C
4530: C++ exception handler used, but unwind semantics are not
enabled. Specify
/EHsc
Microsoft (R) Incremental Linker Version 9.00.21022.08
Copyright (C) Microsoft Corporation. All rights reserved.

C:\>IOSort
Time for reading, sorting, writing: 328 ms
C:\>IOSort
Time for reading, sorting, writing: 328 ms
C:\>IOSort
Time for reading, sorting, writing: 312 ms
C:\>IOSort
Time for reading, sorting, writing: 328 ms
C:\>IOSort
Time for reading, sorting, writing: 312 ms
C:\>IOSort
Time for reading, sorting, writing: 312 ms
C:\>IOSort
Time for reading, sorting, writing: 328 ms

That's same I got berfore. Chaging the file bible2.txt (43 meg file)

C:\>IOSort
Time for reading, sorting, writing: 6938 ms

C:\>IOSort
Time for reading, sorting, writing: 3812 ms

C:\>IOSort
Time for reading, sorting, writing: 3828 ms

C:\>IOSort
Time for reading, sorting, writing: 4250 ms

C:\>IOSort
Time for reading, sorting, writing: 4750 ms

No improvement