Re: how to write a binary file

From:
David Wilkinson <no-reply@effisols.com>
Newsgroups:
microsoft.public.vc.language
Date:
Thu, 24 May 2007 06:28:29 -0500
Message-ID:
<u6HyA5enHHA.3460@TK2MSFTNGP04.phx.gbl>
Ananya wrote:

Well, I was "googleing" for some code, and even though I asked for C++, it
seems I ended up with some C# code, which I cannot use.

So I tried the following C++ code:
unsigned char *pixels = ...
char *charpixels = reinterpret_cast<char*>(pixels);
fstream file;
file.open("chars.dat", ios::out);
file.write(charpixels, count);

Now the code compiled, but it doesn't seem to write the correct byte.
Does reinterpret_cast not work right?

"Ananya" wrote:

I am trying to create a file of bytes from my character array
char* chars with length int count.

I wrote the code:
FileStream file = new FileStream(S"chars.dat", FileMode::Create,
FileAccess::Write);
BinaryWriter binary = new BinaryWriter(file);
binary.write(chars, count);
binary.close();

My compiler doesn't recognize FileStream and BinaryWriter.
I tried:
using namespace System::IO;
but it doesn't recognize that either?

Is my code correct, and what "using" or "include" do I need?
By the way, in new FileStream(S"chars.dat", ...), what does the "S" mean?

Thanks for reading this.


Ananya:

You should decide whether you want to use standard C++ or managed C++.
If the latter I would strongly advise you to move to VS2005 (or wait for
VS2007) because the new C++/CLI syntax is much improved over the Managed
C++ of VS2002/2003. For managed C++ questions, you would also be better
to use the group "microsoft.public.dotnet.languages.vc".

The second code you showed is standard C++. You need to open with
ios::binary.

--
David Wilkinson
Visual C++ MVP

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