UDP client can not recieve data from server in C++ - c++

Question

I am new for C++. I tried to write a UDP client and server in C++. The server can receive data from client. But the client can not receive data from server. No matter what data the server sends, the method recvfrom in client always returns 0.
The client code is below:
#include <winsock2.h>
#include <stdio.h>
#include <string.h>
#include <iostream>
using namespace std;
#pragma comment(lib, "ws2_32.lib")
#define BUFFER_SIZE 1024
int main()
{
SOCKET sock_Client;
WSADATA WSAData;
char receBuf[BUFFER_SIZE];
char sendBuf[BUFFER_SIZE];
if (WSAStartup(MAKEWORD(2, 2), &WSAData) != 0)
{
printf("initialation fails!");
return -1;
}
sock_Client = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
SOCKADDR_IN addr_server;
addr_server.sin_family = AF_INET;
addr_server.sin_port = htons(4567);
addr_server.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
SOCKADDR_IN sock;
int len = sizeof(sock);
while (true)
{
cout << "input data to send:";
cin >> sendBuf;
sendto(sock_Client, sendBuf, strlen(sendBuf), 0, (SOCKADDR*)&addr_server, sizeof(SOCKADDR));
//int last=recv(sock_Client, receBuf, strlen(receBuf), 0); //
int last = recvfrom(sock_Client, receBuf, strlen(receBuf), 0, (SOCKADDR*)&sock, &len);
if (last > 0)
{
receBuf[last] = '\0';
if (strcmp(receBuf, "bye") == 0)
{
cout << "server stops talking..." << endl;
closesocket(sock_Client);
break;
}
else
{
printf("received data：%s\n", receBuf);
}
}
}
closesocket(sock_Client);
WSACleanup();
return 0;
}
The server code:
#include <winsock2.h>
#include <stdio.h>
#include <string.h>
#include <iostream>
using namespace std;
#pragma comment(lib, "ws2_32.lib")
#define BUFFER_SIZE 1024
int main()
{
WSADATA WSAData;
char receBuf[BUFFER_SIZE];
char Response[BUFFER_SIZE];
if (WSAStartup(MAKEWORD(2, 2), &WSAData) != 0)
{
printf("initialation fails!");
exit(1);
}
SOCKET sockServer = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (sockServer == INVALID_SOCKET)
{
printf("Failed socket() \n");
return 0;
}
SOCKADDR_IN addr_Server;
addr_Server.sin_family = AF_INET;
addr_Server.sin_port = htons(4567);
addr_Server.sin_addr.S_un.S_addr = INADDR_ANY;
if (bind(sockServer, (SOCKADDR*)&addr_Server, sizeof(addr_Server)) == SOCKET_ERROR)
{
printf("Failed socket() %d \n", WSAGetLastError());
return 0;
}
SOCKADDR_IN addr_Clt;
int fromlen = sizeof(SOCKADDR);
while (true)
{
int last = recvfrom(sockServer, receBuf, 1024, 0, (SOCKADDR*)&addr_Clt, &fromlen);
if (last > 0)
{
receBuf[last] = '\0';
if (strcmp(receBuf, "bye") == 0)
{
cout << " client stop talking..." << endl;
closesocket(sockServer);
return 0;
}
else
{
printf("received data（%s）：%s\n", inet_ntoa(addr_Clt.sin_addr), receBuf);
}
}
cout << "anser client:";//<br>Response = “”；
cin >> Response;
sendto(sockServer, Response, strlen(Response), 0, (SOCKADDR*)&addr_Clt, sizeof(SOCKADDR));
}
closesocket(sockServer);
WSACleanup();
return 0;
}
Anyone know what is wrong with the code?
The code runs in Windows. So, set(CMAKE_CXX_STANDARD 14) has to be added into CMakeLists.txt. If you want to run the code, please notice that.