C++ in socket programming examples

  • 2020-05-24 05:57:07
  • OfStack

C++, socket programming examples

There are three types of sockets programming: streaming sockets (SOCK_STREAM), datagram sockets (SOCK_DGRAM), original sockets (SOCK_RAW). socket programming based on TCP is using streaming sockets. In this program, add two projects to one workspace. To link a library file for ws2_32.lib.

Steps of server-side programming:

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

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

3: set the socket to listen mode and wait for connection request (listen());

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

5: use the returned socket to communicate with the client (send()/recv());

6: return and wait for another connection request;

7: close the socket, close the loaded socket library (closesocket()/WSACleanup()).

The server-side code is as follows:


#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);
 }

}

Steps of client programming:

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

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

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

4: close the socket, close the loaded socket library (closesocket()/WSACleanup()).

The client code is as follows:


#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();
}

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