本代码是windows系统环境c++(c) socket编程实例。包含客户端和服务端，可以实现客户端发送消息，服务端接收消息并写入日志。 server.cpp为服务端。 client.cpp为客户端。

服务端代码server.cpp：

//by whg 2018-5-23

#include <stdio.h>
#include <stdarg.h>
#include <time.h>

#include<iostream>
#include<WinSock2.h>
#pragma comment(lib, "ws2_32.lib")
#define CONNECT_NUM_MAX 10

using namespace std;


//日志记录
int write_log (char *format) {


	FILE* pFile = fopen("e:\\log.txt", "a");
    fprintf(pFile, "recv:%s\n",format);
	fflush(pFile);
    fclose(pFile);

    return 1;
}


int main()
{
	//加载套接字库
	WSADATA wsaData;
	int iRet = 0;
	iRet = WSAStartup(MAKEWORD(2, 2), &wsaData);
	if (iRet != 0)
	{
		cout << "WSAStartup(MAKEWORD(2, 2), &wsaData) execute failed!" << endl;;
		return -1;
	}
	if (2 != LOBYTE(wsaData.wVersion) || 2 != HIBYTE(wsaData.wVersion))
	{
		WSACleanup();
		cout <<