什么是简单的C或C++ TCP服务器和客户端示例？

#include<iostream>
#include <winsock2.h>
#include <ws2tcpip.h>
#include<thread>
#include<vector>

#pragma comment(lib, "ws2_32.lib")

using namespace std;

void handleClient(SOCKET clientSocket) {
    char buf[1024];
    int len;

    while (true) {
        len = recv(clientSocket, buf, 1024, 0);
        if (len <= 0) break;
        send(clientSocket, buf, len, 0);
    }

    closesocket(clientSocket);
}

int main() {
    WSADATA wsaData;
    int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (iResult != NO_ERROR) {
        cout << "WSAStartup failed: " << iResult<< endl;
        return 1;
    }

    SOCKET listenSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (listenSocket == INVALID_SOCKET) {
        cout << "socket failed: " << WSAGetLastError()<< endl;
        WSACleanup();
        return 1;
    }

    sockaddr_in service;
    service.sin_family = AF_INET;
    service.sin_addr.s_addr = INADDR_ANY;
    service.sin_port = htons(8888);

    if (bind(listenSocket, (SOCKADDR*)&service, sizeof(service)) == SOCKET_ERROR) {
        cout << "bind failed: " << WSAGetLastError()<< endl;
        closesocket(listenSocket);
        WSACleanup();
        return 1;
    }

    if (listen(listenSocket, 5) == SOCKET_ERROR) {
        cout << "listen failed: " << WSAGetLastError()<< endl;
        closesocket(listenSocket);
        WSACleanup();
        return 1;
    }

    vector<thread> threads;

    while (true) {
        SOCKET clientSocket = accept(listenSocket, NULL, NULL);
        if (clientSocket == INVALID_SOCKET) {
            cout << "accept failed: " << WSAGetLastError()<< endl;
            break;
        }

        threads.push_back(thread(handleClient, clientSocket));
    }

    for (auto& t : threads) {
        t.join();
    }

    closesocket(listenSocket);
    WSACleanup();

    return 0;
}

#include<iostream>
#include <winsock2.h>
#include <ws2tcpip.h>

#pragma comment(lib, "ws2_32.lib")

using namespace std;

int main() {
    WSADATA wsaData;
    int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (iResult != NO_ERROR) {
        cout << "WSAStartup failed: " << iResult<< endl;
        return 1;
    }

    SOCKET clientSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (clientSocket == INVALID_SOCKET) {
        cout << "socket failed: " << WSAGetLastError()<< endl;
        WSACleanup();
        return 1;
    }

    sockaddr_in service;
    service.sin_family = AF_INET;
    service.sin_addr.s_addr = inet_addr("127.0.0.1");
    service.sin_port = htons(8888);

    if (connect(clientSocket, (SOCKADDR*)&service, sizeof(service)) == SOCKET_ERROR) {
        cout << "connect failed: " << WSAGetLastError()<< endl;
        closesocket(clientSocket);
        WSACleanup();
        return 1;
    }

    char buf[1024];
    int len;

    while (true) {
        cin.getline(buf, 1024);
        if (strcmp(buf, "exit") == 0) break;

        len = send(clientSocket, buf, strlen(buf), 0);
        if (len <= 0) break;

        len = recv(clientSocket, buf, 1024, 0);
        if (len <= 0) break;

        cout << "Server: "<< buf<< endl;
    }

    closesocket(clientSocket);
    WSACleanup();

    return 0;
}