socket聊天程序（多线程，控制台）

#include <iostream>
#include <winsock2.h>

using namespace std;
#pragma comment(lib, "ws2_32.lib")

char g_ip[20]; //对方ip地址

DWORD WINAPI Receive(
	LPVOID lpParameter   // thread data
	)
{
	SOCKET *psock = (SOCKET*)lpParameter;
	char buf[100];
	SOCKADDR_IN recv_addr;
	int len = sizeof(SOCKADDR);
	char ip[30];
	while (1)
	{
		recvfrom(*psock, buf, 100, 0, (SOCKADDR*)&recv_addr, &len);
		strcpy(ip, inet_ntoa(recv_addr.sin_addr));
		cout << ip << " say:" << buf << endl;
	}
	return 0;
}

DWORD WINAPI Sendto(LPVOID lpParameter)
{
	SOCKET *psock = (SOCKET*)lpParameter;
	char buf[100];
	SOCKADDR_IN addr;
	addr.sin_family = AF_INET;
	addr.sin_addr.S_un.S_addr = inet_addr(g_ip);
	addr.sin_port = htons(6000);

	while (1)
	{
		cin.getline(buf, 100);
		sendto(*psock, buf, 100, 0, (SOCKADDR*)&addr, sizeof(SOCKADDR));
	}
	return 0;
}

int _tmain(int argc, _TCHAR* argv[])
{
	
	WORD wVersionRequested;
	WSADATA wsaData;
	int err;

	wVersionRequested = MAKEWORD( 2, 2 );

	err = WSAStartup( wVersionRequested, &wsaData );
	if ( err != 0 )
	{
		return 0;
	}

	if ( LOBYTE( wsaData.wVersion ) != 2 ||
		HIBYTE( wsaData.wVersion ) != 2 ) 
	{
			WSACleanup( );
			return 0; 
	}

	cout << "please input ip:";
	cin >> g_ip; //对方ip地址

	SOCKET sock = socket(AF_INET, SOCK_DGRAM, 0);
	SOCKADDR_IN addr;
	addr.sin_family = AF_INET;
	addr.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
	addr.sin_port = htons(6000);

	if (bind(sock, (SOCKADDR*)&addr, sizeof(SOCKADDR)) == SOCKET_ERROR)
	{
		cout << "bind fail!" << endl;
		return 0;
	}

	HANDLE hThreadRecv = CreateThread(NULL, 0, Receive, &sock, 0, NULL);  //接收消息线程
	HANDLE hThreadSend = CreateThread(NULL, 0, Sendto, &sock, 0, NULL);   //发送小时线程
	WaitForSingleObject(hThreadRecv, INFINITE);                           //阻塞主线程
	return 0;
}