Client.cpp

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

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

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"

class CurrencyClient {
private:
    SOCKET ConnectSocket = INVALID_SOCKET;

public:
    bool init(const std::string& serverName) {
        WSADATA wsaData;
        int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
        if (iResult != 0) {
            std::cout << "WSAStartup failed: " << iResult << "\n";
            return false;
        }

        struct addrinfo* result = NULL, hints;
        ZeroMemory(&hints, sizeof(hints));
        hints.ai_family = AF_INET;
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_protocol = IPPROTO_TCP;

        iResult = getaddrinfo(serverName.c_str(), DEFAULT_PORT, &hints, &result);
        if (iResult != 0) {
            std::cout << "getaddrinfo failed: " << iResult << "\n";
            WSACleanup();
            return false;
        }

        ConnectSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
        if (ConnectSocket == INVALID_SOCKET) {
            std::cout << "socket failed: " << WSAGetLastError() << "\n";
            freeaddrinfo(result);
            WSACleanup();
            return false;
        }

        iResult = connect(ConnectSocket, result->ai_addr, (int)result->ai_addrlen);
        if (iResult == SOCKET_ERROR) {
            std::cout << "connect failed: " << WSAGetLastError() << "\n";
            closesocket(ConnectSocket);
            ConnectSocket = INVALID_SOCKET;
            WSACleanup();
            return false;
        }

        freeaddrinfo(result);
        return true;
    }

    void run() {
        std::string input;
        char buffer[DEFAULT_BUFLEN];

        while (true) {
            std::cout << "Enter currency pair (e.g. USD EUR) or EXIT: ";
            std::getline(std::cin, input);

            send(ConnectSocket, input.c_str(), static_cast<int>(input.size()), 0);

            if (input == "EXIT") break;

            int iResult = recv(ConnectSocket, buffer, DEFAULT_BUFLEN - 1, 0);
            if (iResult > 0) {
                buffer[iResult] = '\0';
                std::cout << "Rate: " << buffer << std::endl;
            }
        }
    }

    ~CurrencyClient() {
        closesocket(ConnectSocket);
        WSACleanup();
    }
};

int main() {
    CurrencyClient client;
    if (client.init("127.0.0.1")) {
        client.run();
    }
    return 0;
}

Server.cpp

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

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

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"

class CurrencyClient {
private:
    SOCKET ConnectSocket = INVALID_SOCKET;

public:
    bool init(const std::string& serverName) {
        WSADATA wsaData;
        int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
        if (iResult != 0) {
            std::cout << "WSAStartup failed: " << iResult << "\n";
            return false;
        }

        struct addrinfo *result = NULL, hints;
        ZeroMemory(&hints, sizeof(hints));
        hints.ai_family = AF_INET;
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_protocol = IPPROTO_TCP;

        iResult = getaddrinfo(serverName.c_str(), DEFAULT_PORT, &hints, &result);
        if (iResult != 0) {
            std::cout << "getaddrinfo failed: " << iResult << "\n";
            WSACleanup();
            return false;
        }

        ConnectSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
        if (ConnectSocket == INVALID_SOCKET) {
            std::cout << "socket failed: " << WSAGetLastError() << "\n";
            freeaddrinfo(result);
            WSACleanup();
            return false;
        }

        iResult = connect(ConnectSocket, result->ai_addr, (int)result->ai_addrlen);
        if (iResult == SOCKET_ERROR) {
            std::cout << "connect failed: " << WSAGetLastError() << "\n";
            closesocket(ConnectSocket);
            ConnectSocket = INVALID_SOCKET;
            WSACleanup();
            return false;
        }

        freeaddrinfo(result);
        return true;
    }

    void run() {
        std::string input;
        char buffer[DEFAULT_BUFLEN];

        while (true) {
            std::cout << "Enter currency pair (e.g. USD EUR) or EXIT: ";
            std::getline(std::cin, input);

            send(ConnectSocket, input.c_str(), static_cast<int>(input.size()), 0);

            if (input == "EXIT") break;

            int iResult = recv(ConnectSocket, buffer, DEFAULT_BUFLEN - 1, 0);
            if (iResult > 0) {
                buffer[iResult] = '\0';
                std::cout << "Rate: " << buffer << std::endl;
            }
        }
    }

    ~CurrencyClient() {
        closesocket(ConnectSocket);
        WSACleanup();
    }
};

int main() {
    CurrencyClient client;
    if (client.init("127.0.0.1")) {
        client.run();
    }
    return 0;
}