Win32 平臺 C++ socket 編程練習

 使用C++實現Win32平臺的TCP/IP網絡編程，練習socket的使用。

服務端：

#include <iostream>
#include <WinSock2.h>

const unsigned short LISTEN_PORT = 8700;

int main(int argc, char* argv[])
{
	using namespace std;

	WORD wVersionRequested = MAKEWORD(1, 1);
	WSADATA wsaData;

	int err = WSAStartup(wVersionRequested, &wsaData);
	if ( 0 != err )
	{
		cout<<"WSAStartup failed. return: "<<err<<endl;
		return -1;
	}

	if ( wsaData.wVersion != wVersionRequested )
	{
		cout<<"wsaData.wVersion: "<<wsaData.wVersion<<" is not equal to wVersionRequested: "<<wVersionRequested<<endl;
		WSACleanup();
		return -2;
	}

	SOCKET sock = socket(AF_INET, SOCK_STREAM, 0);
	if ( INVALID_SOCKET == sock )
	{
		cout<<"socket error: "<<WSAGetLastError()<<endl;
		return -3;
	}

	SOCKADDR_IN addr_server;
	addr_server.sin_family	= AF_INET;
	addr_server.sin_port	= htons(LISTEN_PORT);
	addr_server.sin_addr.S_un.S_addr = htonl(INADDR_ANY);

	err = bind(sock, (SOCKADDR*)&addr_server, sizeof(addr_server));
	if ( SOCKET_ERROR == err )
	{
		cout<<"bind error: "<<WSAGetLastError()<<endl;
		return -4;
	}

	err = listen(sock, SOMAXCONN);
	if ( SOCKET_ERROR == err )
	{
		cout<<"listen error: "<<WSAGetLastError()<<endl;
		return -5;
	}

	cout<<"Start listening on port "<<LISTEN_PORT<<endl;

	SOCKADDR_IN addr_client;
	int addrlen = sizeof(addr_client);

	while (true)
	{
		SOCKET sock_con = accept(sock, (SOCKADDR*)&addr_client, &addrlen);
		if ( INVALID_SOCKET != sock_con )
		{
			cout<<inet_ntoa(addr_client.sin_addr)<<":"<<ntohs(addr_client.sin_port)<<" connected!"<<endl;

			char recv_buf[256];
			char send_buf[512];

			while (true)
			{
				err = recv(sock_con, recv_buf, sizeof(recv_buf), 0);
				if ( err <= 0 )
				{
					cout<<"recv error: "<<WSAGetLastError()<<endl;
					break;
				}

				sprintf(send_buf, "%s:%d said: %s", inet_ntoa(addr_client.sin_addr), ntohs(addr_client.sin_port), recv_buf);

				cout<<send_buf<<endl;

				sprintf(send_buf, "you said: %s", recv_buf);

				err = send(sock_con, send_buf, strlen(send_buf) + 1, 0);
				if ( SOCKET_ERROR == err )
				{
					cout<<"send error: "<<WSAGetLastError()<<endl;
					break;
				}
			}

			cout<<inet_ntoa(addr_client.sin_addr)<<":"<<ntohs(addr_client.sin_port)<<" left!"<<endl;

			err = closesocket(sock_con);
			if ( SOCKET_ERROR == err )
			{
				cout<<"closesocket error: "<<WSAGetLastError()<<endl;
			}
		}
		else
		{
			cout<<"accept error: "<<WSAGetLastError()<<endl;
		}
	}

	WSACleanup();

	return 0;
}

客戶端：

#include <iostream>
#include <WinSock2.h>

const char* SERVER_IP = "127.0.0.1";
const unsigned short SERVER_PORT = 8700;

int main(int argc, char* argv[])
{
	using namespace std;

	WORD wVersionRequested = MAKEWORD(1, 1);
	WSADATA wsaData;

	int err = WSAStartup(wVersionRequested, &wsaData);
	if ( 0 != err )
	{
		cout<<"WSAStartup failed. return: "<<err<<endl;
		return -1;
	}

	if ( wsaData.wVersion != wVersionRequested )
	{
		cout<<"wsaData.wVersion: "<<wsaData.wVersion<<" is not equal to wVersionRequested: "<<wVersionRequested<<endl;
		WSACleanup();
		return -2;
	}

	SOCKET sock = socket(AF_INET, SOCK_STREAM, 0);
	if ( INVALID_SOCKET == sock )
	{
		cout<<"socket error: "<<WSAGetLastError()<<endl;
		return -3;
	}

	SOCKADDR_IN addr_server;
	addr_server.sin_family	= AF_INET;
	addr_server.sin_port	= htons(SERVER_PORT);
	addr_server.sin_addr.S_un.S_addr = inet_addr(SERVER_IP);

	err = connect(sock, (SOCKADDR*)&addr_server, sizeof(addr_server));
	if ( SOCKET_ERROR == err )
	{
		cout<<"connect error: "<<WSAGetLastError()<<endl;
		return -4;
	}

	cout<<"Connection established."<<endl;

	char send_buf[256];
	char recv_buf[512];

	while (true)
	{
		cin.getline(send_buf, 256);
		cin.clear();	//NOTE: If not clear, when input size overflow, getline will fail the next time.

		if ( 0 == stricmp(send_buf, "quit") || 0 == stricmp(send_buf, "exit") )
			break;

		err = send(sock, send_buf, strlen(send_buf) + 1, 0);
		if ( SOCKET_ERROR == err )
		{
			cout<<"send error: "<<WSAGetLastError()<<endl;
		}

		err = recv(sock, recv_buf, sizeof(recv_buf), 0);
		if ( err <= 0 )
		{
			cout<<"recv error: "<<WSAGetLastError()<<endl;
		}

		cout<<recv_buf<<endl;
	}

	err = closesocket(sock);
	if ( SOCKET_ERROR == err )
	{
		cout<<"closesocket error: "<<WSAGetLastError()<<endl;
	}

	WSACleanup();

	return 0;
}