Programa en Visual C++ en cliente/servidor

Te envio adjunto un codigo de ejemplo que hace uso de Winsock. esta escrito en C++ y es compilable bajo Visual C++. Este ejemplo envia un mensaje al servidor y espera el mensaje de vuelta. El ejemplo funciona en el mismo ordenador, define HOSTNAME como "localhost", o como el nombre de un equipo de la red si quieres hacerlo funcionar dentro de una red.
Espero te sirva de ayuda:
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#include <windows.h>
#include <winsock.h>
#define PORTNUM 5000 // Port number
#define HOSTNAME "localhost" // Server name string
// This should be changed
// according to the server.
int WINAPI WinMain (
HINSTANCE hInstance, // Handle to the current instance
HINSTANCE hPrevInstance,// Handle to the previous instance
LPTSTR lpCmdLine, // Pointer to the command line
int nCmdShow) // Show state of the window
{
int index = 0, // Integer index
iReturn; // Return value of recv function
char szClientA[100]; // ASCII string
TCHAR szClientW[100]; // Unicode string
TCHAR szError[100]; // Error message string
SOCKET ServerSock = INVALID_SOCKET; // Socket bound to the server
SOCKADDR_IN destination_sin; // Server socket address
PHOSTENT phostent = NULL; // Points to the HOSTENT structure
// of the server
WSADATA WSAData; // Contains details of the
// Winsocket implementation
// Initialize Winsocket.
if (WSAStartup (MAKEWORD(1,1), &WSAData) != 0)
{
wsprintf (szError, TEXT("WSAStartup failed. Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
return FALSE;
}
// Create a TCP/IP socket that is bound to the server.
if ((ServerSock = socket (AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
{
wsprintf (szError, TEXT("Allocating socket failed. Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
return FALSE;
}
// Fill out the server socket's address information.
destination_sin.sin_family = AF_INET;
// Retrieve the host information corresponding to the host name.
if ((phostent = gethostbyname (HOSTNAME)) == NULL)
{
wsprintf (szError, TEXT("Unable to get the host name. Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
closesocket (ServerSock);
return FALSE;
}
// Assign the socket IP address.
memcpy ((char FAR *)&(destination_sin.sin_addr),
phostent->h_addr,
phostent->h_length);
// Convert to network ordering.
destination_sin.sin_port = htons (PORTNUM);
// Establish a connection to the server socket.
if (connect (ServerSock,
(PSOCKADDR) &destination_sin,
sizeof (destination_sin)) == SOCKET_ERROR)
{
wsprintf (szError,
TEXT("Connecting to the server failed. Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
closesocket (ServerSock);
return FALSE;
}
// Send a string to the server.
if (send (ServerSock, "To Server.", strlen ("To Server.") + 1, 0)
== SOCKET_ERROR)
{
wsprintf (szError,
TEXT("Sending data to the server failed. Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
}
// Disable sending on ServerSock.
shutdown (ServerSock, 0x01);
for (;;)
{
// Receive data from the server socket.
iReturn = recv (ServerSock, szClientA, sizeof (szClientA), 0);
// Check if there is any data received. If there is, display it.
if (iReturn == SOCKET_ERROR)
{
wsprintf (szError, TEXT("No data is received, recv failed.")
TEXT(" Error: %d"), WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Client"), MB_OK);
break;
}
else if (iReturn == 0)
{
MessageBox (NULL, TEXT("Finished receiving data"), TEXT("Client"),
MB_OK);
break;
}
else
{
// Convert the ASCII string to a Unicode string.
for (index = 0; index <= sizeof (szClientA); index++)
szClientW[index] = szClientA[index];
// Display the string received from the server.
MessageBox (NULL, szClientW, TEXT("Received From Server"), MB_OK);
}
}
// Disable receiving on ServerSock.
shutdown (ServerSock, 0x00);
// Close the socket.
closesocket (ServerSock);
WSACleanup ();
return TRUE;
}