Socket programming steps

There are three types of socket programming: stream socket (sock_stream), datagram socket (sock_dgram), and original socket (sock_raw). TCP-based socket programming is a streaming socket.
In this program, add two projects to a work zone. Link a library file of ws2_32.lib.

Server programming steps:

1: load the socket library and create a socket (wsastartup ()/socket ());

2: bind a socket to an IP address and a port (BIND ());

3: Set the socket to listening mode and wait for the connection request (Listen ());

4: after the request arrives, accept the connection request and return a new socket (accept () corresponding to the connection ());

5: Use the returned socket to communicate with the client (send ()/Recv ());

6: return. Wait for another connection request;

7. Close the socket and the loaded socket Library (closesocket ()/wsacleanup ()).

The server code is as follows:

# Pragma comment (Lib, "ws2_32.lib") // This sentence is very important. No compilation error occurs.
# Include <stdio. h>
# Include <winsock2.h>
Void main ()
{
Word wversionrequested;
Wsadata;
Int err;

Wversionrequested = makeword (1, 1 );

Err = wsastartup (wversionrequested, & wsadata );
If (Err! = 0 ){
Return;
}

If (lobyte (wsadata. wversion )! = 1 |
Hibyte (wsadata. wversion )! = 1 ){
Wsacleanup ();
Return;
}
Socket socksrv = socket (af_inet, sock_stream, 0 );

Sockaddr_in addrsrv;
Addrsrv. sin_addr.s_un.s_addr = htonl (inaddr_any );
Addrsrv. sin_family = af_inet;
Addrsrv. sin_port = htons (6000 );

BIND (socksrv, (sockaddr *) & addrsrv, sizeof (sockaddr ));

Listen (socksrv, 5 );

Sockaddr_in addrclient;
Int Len = sizeof (sockaddr );
While (1)
{
Socket sockconn = accept (socksrv, (sockaddr *) & addrclient, & Len );
Char sendbuf [50];
Sprintf (sendbuf, "Welcome % s to here! ", Inet_ntoa (addrclient. sin_addr ));
Send (sockconn, sendbuf, strlen (sendbuf) + 1, 0 );
Char recvbuf [50];
Recv (sockconn, recvbuf, 50, 0 );
Printf ("% s \ n", recvbuf );
Closesocket (sockconn );
}
}

Client programming steps:

1: load the socket library and create a socket (wsastartup ()/socket ());

2: Send a connection request (connect () to the server ());

3: communicate with the server (send ()/Recv ());

4: Close the socket and close the loaded socket Library (closesocket ()/wsacleanup ()).

The client code is as follows:

# Pragma comment (Lib, "ws2_32.lib") // This sentence is very important. No compilation error occurs.
# Include <stdio. h>
# Include <winsock2.h>
Void main ()
{
Word wversionrequested;
Wsadata;
Int err;

Wversionrequested = makeword (1, 1 );

Err = wsastartup (wversionrequested, & wsadata );
If (Err! = 0 ){
Return;
}

If (lobyte (wsadata. wversion )! = 1 |
Hibyte (wsadata. wversion )! = 1 ){
Wsacleanup ();
Return;
}
Socket sockclient = socket (af_inet, sock_stream, 0 );

Sockaddr_in addrsrv;
Addrsrv. sin_addr.s_un.s_addr = inet_addr ("127.0.0.1 ");
Addrsrv. sin_family = af_inet;
Addrsrv. sin_port = htons (6000 );
Connect (sockclient, (sockaddr *) & addrsrv, sizeof (sockaddr ));
Send (sockclient, "hello", strlen ("hello") + 1, 0 );
Char recvbuf [50];
Recv (sockclient, recvbuf, 50, 0 );
Printf ("% s \ n", recvbuf );

Closesocket (sockclient );
Wsacleanup ();
}

Run the following command: the server is on the left and the client on the right. After the connection is successful, the server sends "Welcome 127.0.0.1 to here!" to the customer !" Information, from the client
The server sends "hello"