Socket programming - long connection mode - sockets

Question

As the picture shows,when in the long connection mode,the server recv and send,the client send and recv.And my question is:
Can I only just use the send in the client and just use the recv in the server?
The test code:
The server:
//#include "stdafx.h"
#include <stdio.h>
#include <winsock2.h>
#pragma comment(lib,"ws2_32.lib")
int main(int argc, char* argv[])
{
WORD sockVersion = MAKEWORD(2, 2);
WSADATA wsaData;
if (WSAStartup(sockVersion, &wsaData) != 0)
{
return 0;
}
SOCKET slisten = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (slisten == INVALID_SOCKET)
{
printf("socket error !");
return 0;
}
sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_port = htons(8888);
sin.sin_addr.S_un.S_addr = INADDR_ANY;//
if (bind(slisten, (LPSOCKADDR)&sin, sizeof(sin)) == SOCKET_ERROR)
{
printf("bind error !");
}
if (listen(slisten, 30) == SOCKET_ERROR)
{
printf("listen error !");
return 0;
}
SOCKET sClient;
sockaddr_in remoteAddr;
int nAddrlen = sizeof(remoteAddr);
char revData[255];
while (true)
{
printf("waitting...\n");
sClient = accept(slisten, (SOCKADDR *)&remoteAddr, &nAddrlen);
if (sClient == INVALID_SOCKET)
{
printf("accept error !");
continue;
}
printf("receive a connection：%s \r\n", inet_ntoa(remoteAddr.sin_addr));
char * sendData = "R\n";
//
while (1)
{
int ret = recv(sClient, revData, 255, 0);
if (ret > 0)
{
revData[ret] = 0x00;
printf(revData);
//new add code
//send(sClient, sendData, strlen(sendData), 0);
}
else
break;
}
closesocket(sClient);
}
closesocket(slisten);
WSACleanup();
return 0;
}
The client:
//#include "stdafx.h"
#include <WINSOCK2.H>
#include <STDIO.H>
#pragma comment(lib,"ws2_32.lib")
int main(int argc, char* argv[])
{
WORD sockVersion = MAKEWORD(2, 2);
WSADATA data;
if (WSAStartup(sockVersion, &data) != 0)
{
return 0;
}
SOCKET sclient = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sclient == INVALID_SOCKET)
{
printf("invalid socket !");
return 0;
}
sockaddr_in serAddr;
serAddr.sin_family = AF_INET;
serAddr.sin_port = htons(8888);
serAddr.sin_addr.S_un.S_addr = inet_addr("10.92.1.148");
if (connect(sclient, (sockaddr *)&serAddr, sizeof(serAddr)) == SOCKET_ERROR)
{
printf("connect error !");
closesocket(sclient);
return 0;
}
char * sendData = "T\n";
int cnt = 0;
char recData[255];
while (1)
{
send(sclient, sendData, strlen(sendData), 0);
//new add code
//int ret = recv(sclient, recData, 255, 0);
//if (ret > 0)
//{
// recData[ret] = 0x00;
// printf(recData);
//}
}
printf("cnt=%d\n",cnt);
closesocket(sclient);
WSACleanup();
return 0;
}
The code is wrong when I test.While when I add the new code,the program can run.The new code is the code after the // as the above .So I think just have send in one side and recv in another side maybe wrong.It have to have a loop.Is it right?Must I have a loop(request and response loop in the picture)?