C ++ Socket programming steps and socket programming steps

C ++ Socket programming steps and 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.

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();
}