c++ Convert string to bytes to send over tcp

Question

I'm trying to send a 28 character string to a remote ip address and port. I've done this successfully in vb.net using the following code snippets:

Dim swon As String = "A55A6B0550000000FFFBDE0030C8"
Dim sendBytes As [Byte]()
sendBytes = Encoding.ASCII.GetBytes(swon)
netStream.Write(sendBytes, 0, sendBytes.Length)

I now have to convert this across to c++ and have the following so far:

char *swon = "A55A6B0550000000FFFBDE0030C8";
array<Byte>^ sendBuffer = gcnew array<Byte>(bufferSize);
sendBuffer = BitConverter::GetBytes( swon );
tcpStream->Write(sendBuffer, 0, sendBuffer->Length);

but am getting stuck at this point. I'm sure I'm missing a simple syntax error but I can't figure it out!

To clarify, I'm not getting an error, but I don't think the string is being converted to bytes correctly as when I convert back, I just get a '01'

Cheers, Chris

Answer 1

I don't understand why you are not just using the exact same .Net framework classes in your ++/CLI code. eg. System::String for swon, Encoding::ASCII to produce the array of bytes.

Anything you did in VB you can map directly over to C++/CLI without using different classes - that's the easest port for you. When you are in MSDN online, just select the C++ view to get examples of stuff you want to do. Try that on this page, for example: http://msdn.microsoft.com/en-us/library/system.text.encoding.ascii.aspx

Answer 2

Steve is correct that the same logic can be duplicated in C++. But the C++ char* already is ASCII, no conversion is necessary. Just a copy is all that's needed.

const char swon[] = { "A55A6B0550000000FFFBDE0030C8" };
array<Byte>^ sendBuffer = gcnew array<Byte>((sizeof swon) - 1);
pin_ptr<Byte> startBuffer = &sendBuffer[0];
memcpy(startBuffer, swon, sendBuffer->Length);
tcpStream->Write(sendBuffer, 0, sendBuffer->Length);