ask

Hi cuong5985,
> >can i ask someone what is external file name for I/O Stream???

What do you mean by external file name?

David Maisonave :-)
Cheers!

Just like i have a program like this:
#include <fstream>
#include <iostream.h>
#include <stdlib.h>

int main()
{
using namespace std;
ifstream in_stream;
ofstream out_stream;

in_stream.open("infile.dat");
out_stream.open("outfile.dat");

int first, second, third;
in_stream >> first >> second>> third;
out_stream <<"The sum of the first 3\n"
           <<"numbers in infile.dat\n"
           <<"is" <<(first+second+third)
           <<endl;
in_stream.close( );
out_stream.close( );

      system("PAUSE");
      return 0;
}

So where is my infile.dat located????

>>So where is my infile.dat located????

This depends no your implementation, OS, and IDE.

If you want to be sure of it's location, you should give it a fully qualified name (full path).

Without a fully qualified name, it could be located in one of the follownig directories:
The path of your executable
The path were you launched your executable
The path of your current directory when file is opened

FYI:
You should not use ifstream.h and iostream.h
They're not part of the C++ standard, and therefore they're not portable and will not compile on compilers like VC++ 7.x

Use <iostream> and <fstream> instead, which are part of the C++ standard.

have u wriiten the program ur self or gotten it from somewhere

I just want to give an example and get that example from a book.  THanks for your comment.