C ++ network programming review

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.

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 ()).

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 ()).

Method 1: load/release the Winsock database:

1. Loading Method:

Wsadata WSA;
/* Initialize socket Resources */
If (wsastartup (makeword (1,1), & WSA )! = 0)
{
Return; // indicates an error.
}

2. Release Method:

Wsacleanup ();

Method 2: Construct a socket:

1. SERVER: Construct a listener socket and a streaming socket.
SocketListen_sock= Socket (af_inet, sock_stream, 0)

2. Client: Construct communication socket and stream socket.
Socket Client_ Sock= Socket (af_inet, sock_stream, 0)

Method 3: configure the listening address and port:

1. SERVER: sockaddr_inServeraddr
Zeromemory (char *)&Serveraddr, Sizeof (Serveraddr));
Serveraddr. Sin_family =Af_inet;
Serveraddr. Sin_port = htons (1234);/* Local port: 1234 */
Serveraddr. Sin_addr.s_addr = htonl (Inaddr_any);/* With IP */

Method 4: bind a socket:

1. SERVER: bind the listening socket.
BIND (Listen_sock,(Struct sockaddr *)&Serveraddr,Sizeof (Serveraddr))

Method 5: Server/client connection:

1. SERVER: Waiting for client access.
SocketCommand_sock= Accept (Listen_sock,...)

2. Client: request to connect to the server.
Int ret = connect (Client_sock,...)

Method 6: receive/send data:

1. SERVER: Wait for the client to access. Char Buf [1024].
Receive data: Recv (Command_sock, Buf ,...)
Or
Send data: Send (Command_sock, Buf ,...)

2. Client: request to connect to the server. Char Buf [1024].
Send data: Send (Client_ Sock, Buf ,...)
Or
Receive data: Recv (Client_ Sock, Buf ,...)

Method 7: Disable socket:

1. SERVER: Disable socket.
Closesocket (Listen_sock)
Closesocket (Command_sock)

2. Client: Disable socket.
Closesocket (Client_sock)

?

#include <stdio.h>#include <Winsock2.h>void main(){ WORD wVersionRequested; WSADATA 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); } }

#include <stdio.h>#include <Winsock2.h>void main(){ WORD wVersionRequested; WSADATA 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();}