In this sample server sends message (hard-coded) to client. Client shows the
message in its console:

This message is sent by the Server ...

The sample works with 2 console applications SocketServer and SocketClient. 
Server gets socket descriptor with socket function, creates a socket name by
filling sockaddr_in structure, assigns the name to created socket descriptor
by bind function and goes into listening state calling listen function.
This socket will serve as listening socket. At this point server waits for 
incoming connections and listen does not return until connection is made up. 
When client successfully calls connect, listen (on server) returns and server 
calls accept creating a new socket for the established connection.
Before calling accept socket handle for new connection is defined with
socket function and sockaddr_in variable is defined, but not filled, for
this connection. It is the accept function that actually returns a handle
to a socket assosiated with new connection and filles sockaddr_in (though
the structure is filled it is not necessary used). Once accept succeeds
a server can send a message to a client by send function. Accordingly,
client reads the message with recv function (short of receive).

Here are steps for making simple client-server communication using blocking
sockets in schematic view:


SERVER                             CLIENT
------                             ------

- calls socket to open           - calls socket to create socket on client 
listening socket;                  side to connect, socket-to-socket type,
                                   to socket on server;
- server socket name is created    - client socket name is created 
by filling sockaddr_in structure;  by filling sockaddr_in structure;

- listening socket name is bound
to socket descriptor by bind
function called on server only;

- using handle to listening
socket the server calls listen
to listen for incoming connection
from client;

                                   - calls connect to establish a connection
                                   to server;
- once connect is called on 
client listen returns and server
calles accept which returns  a new
descriptor for a new server
socket associated on server with
this connection;

- using socket descriptor returned
by accept, server sends a message
to client by calling send;
                                   - client reads message from server by 
                                   calling recv;