服务端（server.cpp）：

#include <stdlib.h>
#include <stdio.h>
#include <winsock2.h>
#include <time.h>
#include <conio.h>
#include <windows.h>
#include <process.h>
#include <math.h>

#define QLEN 5
#define WSVERS MAKEWORD(2, 0)
#define BUFLEN 2000
#pragma comment(lib,"ws2_32.lib")

SOCKET msock, ssock;
SOCKET  sockets[100] = {NULL};

int cc;
time_t now;
char pts[64];
char buf[2000];
char *input;
HANDLE hThread1,hThread[100] = {NULL};

unsigned int threadID,ThreadID[105],number;
char *name[105];

struct  sockaddr_in fsin;
struct  sockaddr_in Sin;

unsigned int __stdcall Chat(PVOID PM) {

	(void) time(&now);
	strftime(pts,sizeof(pts),"%Y-%m-%d",localtime(&now));

	sprintf(pts,"%s.txt",pts);

	FILE *fp=fopen(pts,"a");;
	if((fp=fopen(pts,"a")) == NULL) {
		printf("ERROR:data file cannot be opened!\n");
		exit(1);
	}

	char buf1[2000];
	char buf2[2000];
	char buf3[2000];
	char buf4[2000];
	char buf15[2000];

	(void) time(&now);
	strftime(pts,sizeof(pts),"%Y,%b,%d %X %a",localtime(&now));

	fprintf(fp,"*-*-*-*-*[%s]*-*-*-*-*\n\n",pts);

	(void) time(&now);
	strftime(pts,sizeof(pts),"%X",localtime(&now));

	sockets[number] = ssock;
	SOCKET  sock = ssock;
	ThreadID[number] = threadID;
	unsigned int threadid = threadID;
	char namei[20];

	(void) recv(sock,namei, BUFLEN, 0);
	name[number]=namei;

	sprintf(buf1,"[我的进程号:%d]\n",threadid);
	sprintf(buf15,"[我的昵称:%s]\n",name[number]);

	(void) send(sock,buf1, sizeof(buf1), 0);
	(void) send(sock,buf15, sizeof(buf15), 0);
	sprintf(buf2,"<%s> %s\n加入了聊天室！\n",namei,pts);

	printf("%s",buf2);
	fprintf(fp,"%s",buf2);

	for(int i=0; i<=number; i++) {
		if(sockets[i] != NULL && sockets[i] != sock) {
			(void) send(sockets[i],buf2, sizeof(buf2), 0);
			printf("(成功将消息发送至<%d>)\n",ThreadID[i]);
		}
	}

	puts("");
	fprintf(fp,"\n");

flag1:
	cc = recv(sock, buf3, BUFLEN, 0);

	if(cc == SOCKET_ERROR || cc == 0) {

		(void) time(&now);
		strftime(pts,sizeof(pts),"%X",localtime(&now));

		sprintf( buf3,"<%s> %s\n离开了聊天室！\n",namei,pts);

		sock = NULL;
		sockets[number] = NULL;
		CloseHandle(hThread[number]);

		printf("%s", buf3);
		fprintf(fp,"%s", buf3);

		for(int i=0; i<=number; i++) {
			if(sockets[i] != NULL && sockets[i] != sock) {
				(void) send(sockets[i], buf3, sizeof(buf3), 0);
				printf("(成功将消息发送至<%d>)\n",ThreadID[i]);
			}
		}

		puts("");
		fprintf(fp,"\n");

	}

	else if(cc > 0) {

		(void) time(&now);
		strftime(pts,sizeof(pts),"%X",localtime(&now));
		sprintf(buf4,"<%s> %s\n%s\n",namei,pts,buf3);

		printf("%s",buf4);
		fprintf(fp,"%s",buf4);

		for(int i=0; i<=number; i++) {
			if(sockets[i] != NULL && sockets[i] != sock) {
				(void) send(sockets[i],buf4, sizeof(buf4), 0);
				printf("(成功将消息发送至<%d>)\n",ThreadID[i]);
			}
		}

		puts("");
		fprintf(fp,"\n");

		goto flag1;
	}
	(void) closesocket(sock);

	return 0;
}

int main(int argc, char *argv[]) {
	int alen;
	WSADATA wsadata;

	char  service[10];

	printf("请输入服务器端口：");
	gets(service);

	//注意：客户端连接服务端，IP为服务端的计算机的IP，端口为上面的service

	WSAStartup(WSVERS, &wsadata);
	msock = socket(PF_INET, SOCK_STREAM, 0);
	memset(&Sin, 0, sizeof(Sin));

	Sin.sin_family = AF_INET;
	Sin.sin_addr.s_addr = INADDR_ANY;
	Sin.sin_port = htons((u_short)atoi(service));
	bind(msock, (struct sockaddr *)&Sin, sizeof(Sin));
	listen(msock, 5);

	system("cls");

	printf("机房聊天工具【服务端】\n");
	printf("服务器端口：[%s]\n",service);

	(void) time(&now);
	strftime(pts,sizeof(pts),"%Y/%m/%d %X",localtime(&now));
	printf("时间:%s\n-----------------------\n",pts);

	number = -1;

	while(1) {

		alen = sizeof(struct sockaddr);
		ssock = accept(msock, (struct sockaddr *)&fsin, &alen);
		number ++;
		hThread[number] = (HANDLE)_beginthreadex(NULL, 0,Chat,NULL, 0, &threadID);
		//(void) recv(ssock, name[number], BUFLEN, 0);

	}

	(void) closesocket(msock);
	WSACleanup();

	return 0;
}

客户端（client.cpp）：

#include <stdlib.h>
#include <stdio.h>
#include <winsock2.h>
#include <time.h>
#include <windows.h>
#include <process.h>
#include <math.h>

#define BUFLEN 2000
#define WSVERS MAKEWORD(2, 0)
#pragma comment(lib,"ws2_32.lib")

SOCKET    sock,sockets[100] = {NULL};
char    *packet = NULL;
char *pts,*input;
HANDLE hThread;
unsigned threadID;

unsigned int __stdcall Chat(PVOID PM ) {
	time_t    now;
	(void) time(&now);
	pts = ctime(&now);
	char buf[2000];

	while(1) {
		int cc = recv(sock, buf, BUFLEN, 0);
		if(cc == SOCKET_ERROR|| cc == 0) {
			printf("错误:%d.----",GetLastError());
			printf("与服务器失去连接！\n");
			CloseHandle(hThread);
			(void)closesocket(sock);
			break;
		} else if(cc > 0) {
			printf("%s\n",buf);
		}
	}
	return 0;
}

int main(int argc, char *argv[]) {
	
	time_t    now;
	(void) time(&now);
	pts = ctime(&now);
	
	char host[50],service[10];
	
	printf("请输入服务器IP地址：");
	gets(host);//IP为服务端的计算机的IP 
	
	printf("请输入服务器端口：");
	gets(service);//端口请自行更改 
	
	struct  sockaddr_in sin;
	WSADATA wsadata;
	WSAStartup(WSVERS, &wsadata);

	memset(&sin, 0, sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_port = htons((u_short)atoi(service));
	sin.sin_addr.s_addr = inet_addr(host);

	sock = socket(PF_INET, SOCK_STREAM,0);
	
	system("cls");
	
	printf("您已连接至：\nIp：[%s]\n端口：[%s]\n\n",host,service);
	
	char namei[20];
	printf("请输入您的昵称：");
	gets(namei);

	connect(sock, (struct sockaddr *)&sin, sizeof(sin));
	
	(void) send(sock,namei, sizeof(namei), 0);
	
	system("cls");

	printf("*-----------------------------*\n");
	printf("|         机房聊天工具        |\n");
	printf("|          【客户端】         |\n");
	printf("|   提示：输入\'help\'查看指令  |\n");
	printf("*-----------------------------*\n");
	
	hThread = (HANDLE)_beginthreadex(NULL, 0,Chat, NULL, 0, &threadID);
	
	while(1) {
		
		char buf1[2000];
		gets(buf1);
		
		if(!strcmp(buf1 ,"help")){
			puts("");
			puts("---------------------");
			puts("机房聊天工具 命令大全");
			puts("help 查看命令");
			puts("exit 退出聊天室");
			puts("---------------------");
			puts("");
		}
		
		if(!strcmp(buf1 ,"exit"))
			goto end;
		
		(void) send(sock,buf1, sizeof(buf1), 0);
		
		(void) time(&now);
		pts = ctime(&now);
		
	}

end:
	CloseHandle(hThread);
	closesocket(sock);
	WSACleanup();

	printf("按任意键以继续...\n");
	getchar();
	return 0;
}

注意事项：在编译源代码时需加上-lwsock32一句（以Dev-C++为例，点击[工具 Tools]->[编译选项 Compiler Opitions]，然后在[编译时加入以下命令 Add the following commands when calling the complier]一栏加入-lwsock32） 原文