server

#define _CRT_SECURE_NO_DEPRECATE

#include <stdio.h> 
#include <winsock2.h>
#include <winsock2.h>

#define SERVER_PORT 5208 //侦听端口

#pragma comment(lib,"wsock32.lib")

int main()
{
    WORD wVersionRequested;
    WSADATA wsaData;
    int ret, nLeft, length, flag;
    SOCKET sListen, sServer; //侦听套接字，连接套接字
    struct sockaddr_in saServer, saClient; //地址信息   
    char *ptr;//用于遍历信息的指针   
    //WinSock初始化
    wVersionRequested=MAKEWORD(2, 2); //希望使用的WinSock DLL 的版本
    ret=WSAStartup(wVersionRequested, &wsaData);
    if(ret!=0)
    {
        printf("WSAStartup() failed!\n");
        return 6;
    }
    //创建Socket,使用TCP协议
    sListen=socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (sListen == INVALID_SOCKET)
    {
        WSACleanup();
        printf("socket() faild!\n");
        return 5;
    }
    //构建本地地址信息
    saServer.sin_family = AF_INET; //地址家族
    saServer.sin_port = htons(SERVER_PORT); //注意转化为网络字节序
    saServer.sin_addr.S_un.S_addr = htonl(INADDR_ANY); //使用INADDR_ANY 指示任意地址
  
    //绑定
    ret = bind(sListen, (struct sockaddr *)&saServer, sizeof(saServer));
    if (ret == SOCKET_ERROR)
    {
        printf("bind() faild! code:%d\n", WSAGetLastError());
        closesocket(sListen); //关闭套接字
        WSACleanup();
        return 4;
    }
  
    //侦听连接请求
    ret = listen(sListen, 5);
    if (ret == SOCKET_ERROR)
    {
        printf("listen() faild! code:%d\n", WSAGetLastError());
        closesocket(sListen); //关闭套接字
        return 3;
    }
  
    printf("Waiting for client connecting!\n\n");
    //阻塞等待接受客户端连接
	while(1)//循环监听客户端，永远不停止，所以，在本项目中，我们没有心跳包。
	{
		length = sizeof(saClient);
		sServer = accept(sListen, (struct sockaddr *)&saClient, &length);
		if (sServer == INVALID_SOCKET)
		{
			printf("accept() faild! code:%d\n", WSAGetLastError());
			closesocket(sListen); //关闭套接字
			WSACleanup();
			return 2;
		}       
		char receiveMessage[100],message[100];
		ret = recv(sServer, receiveMessage, 100, 0);
		if (ret == SOCKET_ERROR)
		{
			printf("recv() failed!\n");
			return 1;
		}
		if (ret == 0) //客户端已经关闭连接
		{
			printf("Client has closed the connection\n");
			break;
		}
		printf("%s\n",receiveMessage);
		while(1)
		{		//chat!
			printf("1.just listen\t2.say something: ");
			scanf("%d",&flag);
			if(flag==1)
			{
				ret = recv(sServer, receiveMessage, 100, 0);
				if (ret == SOCKET_ERROR)
				{
					printf("recv() failed!\n");
					return 1;
				}
				if (ret == 0) //客户端已经关闭连接
				{
					printf("Client has closed the connection\n");
					break;
				}
				printf("Client said:  %s\n",receiveMessage);
			}
			//system("pause");
			/*nLeft -= ret;
			ptr += ret;*/
			if(flag == 2)
			{
				printf("\nEnter what you wanna say:\n");
				getchar();
				gets(message);
				ret = send (sServer, (char *)&message, sizeof(message), 0);
				if (ret == SOCKET_ERROR)
				{
					printf("recv() failed!\n");
					return 1;
				}
				if (ret == 0) //客户端已经关闭连接
				{
					printf("Client has closed the connection\n");
					break;
				}
			}
		}  
		//printf("receive message:%s\n", receiveMessage);//打印我们接收到的消息。
 
	} 
	//  closesocket(sListen);
	//  closesocket(sServer);
	//  WSACleanup();
}