Client.cpp

#define WIN32_LEAN_AND_MEAN
#include <iostream>
#include <string>
#include <thread>
#include <ws2tcpip.h>

using namespace std;

#pragma comment(lib,"Ws2_32.lib")

void receiveThread(SOCKET s)
{
    while (true)
    {
        char buffer[512]{};
        int bytes = recv(s, buffer, 511, 0);
        if (bytes <= 0) break;
        buffer[bytes] = '\0';
        cout << "\nServer: " << buffer << endl;
    }
}

int main()
{
    WSADATA wsa;
    WSAStartup(MAKEWORD(2, 2), &wsa);

    addrinfo hints{};
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;

    addrinfo* result;

    getaddrinfo("localhost", "27015", &hints, &result);
    SOCKET s = socket(result->ai_family,result->ai_socktype,result->ai_protocol);
    connect(s, result->ai_addr, (int)result->ai_addrlen);

    freeaddrinfo(result);

    cout << "Connected to server\n";

    thread(receiveThread, s).detach();

    while (true)
    {
        string cmd;
        cout << "\nEnter command: ";
        getline(cin, cmd);

        send(s, cmd.c_str(), cmd.size(), 0);
        if (cmd == "exit") break;
    }

    closesocket(s);
    WSACleanup();
}

Server.cpp

#define WIN32_LEAN_AND_MEAN
#include <iostream>
#include <string>
#include <thread>
#include <ctime>
#include <ws2tcpip.h>

using namespace std;

#pragma comment(lib,"Ws2_32.lib")

string getTime()
{
    time_t now = time(0);
    tm t;
    localtime_s(&t, &now);

    char buf[32];
    sprintf_s(buf, "%02d:%02d:%02d", t.tm_hour, t.tm_min, t.tm_sec);

    return buf;
}

string getDate()
{
    time_t now = time(0);
    tm t;
    localtime_s(&t, &now);
    char buf[32];
    sprintf_s(buf, "%02d.%02d.%d", t.tm_mday,t.tm_mon + 1, 1900 + t.tm_year);

    return buf;
}

void processRequest(SOCKET client, string request)
{
    string answer;

    if (request == "time")
        answer = "Time: " + getTime();

    else if (request == "date")
        answer = "Date: " + getDate();

    else if (request.find("weather") == 0)
    {
        string city = request.substr(8);
        answer = "Weather in " + city + ": +18C sunny";
    }

    else if (request == "eur")
        answer = "EUR rate: 42.30";

    else if (request == "btc")
        answer = "BTC rate: 65000$";

    else
        answer = "Unknown command";

    send(client, answer.c_str(), answer.size(), 0);
}

int main()
{
    WSADATA wsa;
    WSAStartup(MAKEWORD(2, 2), &wsa);

    addrinfo hints{};
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
    hints.ai_flags = AI_PASSIVE;

    addrinfo* result;
    getaddrinfo(NULL, "27015", &hints, &result);

    SOCKET listenSocket = socket(result->ai_family,result->ai_socktype, result->ai_protocol);

    bind(listenSocket, result->ai_addr, (int)result->ai_addrlen);
    freeaddrinfo(result);

    listen(listenSocket, SOMAXCONN);

    cout << "Server started...\n";
    SOCKET client = accept(listenSocket, NULL, NULL);
    cout << "Client connected\n";

    while (true)
    {
        char buffer[512]{};
        int bytes = recv(client, buffer, 511, 0);
        if (bytes <= 0) break;
        buffer[bytes] = '\0';
        string request = buffer;
        if (request == "exit") break;
        cout << "Request: " << request << endl;
        thread(processRequest, client, request).detach();
    }
    closesocket(client);
    WSACleanup();
}