Summary of VC ++ network programming (1)

1. socket programming principles

A complete inter-network communication process must be composed of two processes and can only use the same high-level protocol. That is to say, TCP is not allowed for communication, and UDP is used for the other end. A complete network information must be identified by a quintuple: Protocol, local address, local port number, remote address, and remote port number.

1.1 Client/Server Communication Model

In Client/Server mode, we turn the party requesting the service into a customer, and the party providing a service is called the Server)

A service program listens to service requests at a well-known address, that is, the service process remains dormant until a client initiates a connection request to the service address. At this moment, the service program is "awakened" and provides services to the customer-responds appropriately to the customer's request. Although link-based services are the standard for designing client/server applications, some services can also be provided through connectionless interfaces.

The request/Response Process of the customer and/server is as follows:

Comment (lib, "WS2_32") <stdio. h> printf (= MAKEWORD (, (WSAStartup (wVersionRequested, & wsaData )! = SOCKET s = (s ==== htons (= inet_addr (connect (s, (sockaddr *) & Sadd, (Sadd) = printf (

========= Server

#include <winsock2.h><stdio.h> comment(lib,"ws2_32") main( argc, *    WORD wVersionRequested = MAKEWORD(,(WSAStartup(wVersionRequested,&wsaData) != ,&wsaData.szDescription[,&wsaData.szSystemStatus[=(s ==    == htons(= inet_addr((bind(s,(sockaddr*)&Sadd,(Sadd)) ==      ( listen( s,  )==      caddLen= = accept( s,( sockaddr*)& Cadd,& ( c== ,& ( xx==  || xx==  

Running result: