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

On Thu, 20 Mar 2008 10:36:20 +0000 (UTC), Lionel B <me@privacy.net>
wrote:


By the way, have look at 2001 post where I used set...

http://groups.google.com/group/comp.lang.c++/msg/695ebf877e25b287

In that case, it didn't make a difference because bible.txt I was
using had verse numbers (so there could be no duplicates). A few here
(including Pete Becker from dinkumware) claimed that I used set and it
was unfair...

In any case, I can use multiset...

Time for reading, sorting, writing: 328 ms (c++)
Time for reading, sorting, writing: 312 ms (c++)
Time for reading, sorting, writing: 312 ms (c++)

Just a little improvement only...

For Java I can try TreeSet
http://java.sun.com/javase/6/docs/api/java/util/TreeSet.html

(which I asume does something similiar -- if not, any Java expert can
correct it).

Time for reading, sorting, writing: 359 ms
Time for reading, sorting, writing: 360 ms
Time for reading, sorting, writing: 359 ms

Not much changes here ...

------ c++-------
#include <fstream>
#include<iostream>
#include <string>
#include <set>
#include <algorithm>
#include <ctime>
using namespace ::std;
using namespace std;

void main()
{
   multiset<string> buf;
   string linBuf;
   ifstream inFile("bible.txt");

   clock_t start=clock();
   while(getline(inFile,linBuf))
       buf.insert(linBuf);
   ofstream outFile("output.txt");
   copy(buf.begin(),buf.end(),ostream_iterator<string>(outFile,"\n"));
clock_t endt=clock();
   cout <<"Time for reading, sorting, writing: " << endt-start << "
ms\n";

}

-------- java -----------

import java.io.*;
import java.util.*;
public class IOSort
{
    public static void main(String[] arg) throws Exception
   {
            Collection<String> ar = new TreeSet<String> ();
            String line = "";
            BufferedReader in = new BufferedReader( new
FileReader("bible.txt"));
            PrintWriter out = new PrintWriter(new BufferedWriter(new
FileWriter("output.txt")));
            long start = System.currentTimeMillis();
            while (true)
            { line = in.readLine();
              if (line == null)
                  break;
                ar.add(line);
            }
            int size = ar.size();
            for (String c : ar)
            {
                out.println(c);
            }
            out.close();
            long end = System.currentTimeMillis();
           System.out.println("Time for reading, sorting, writing: "+
(end - start) + " ms");
   }

}