non blocking server

#pragma comment (lib, "WS2_32.lib")
#include <WinSock2.h>
#include <windows.h>
#include <iostream>
#include <vector>
std::vector<SOCKET> Connections;
int main() {
    WSADATA wsaData;
    WSAStartup(MAKEWORD(2, 1), &wsaData);
    SOCKADDR_IN addr;
    int sizeofaddr = sizeof(addr);
    addr.sin_addr.s_addr = INADDR_ANY;
    addr.sin_port = htons(80);
    addr.sin_family = AF_INET;
    SOCKET listenSocket = socket(AF_INET, SOCK_STREAM, NULL);
    bind(listenSocket, (SOCKADDR*)(&addr), sizeofaddr);
    listen(listenSocket, SOMAXCONN);
    u_long iMode = 1;
    ioctlsocket(listenSocket, FIONBIO, &iMode);
    FD_SET readfds;
    std::cout << "Running on 127.0.0.1:80..." << std::endl;
    while (1) {
        FD_ZERO(&readfds);
        FD_SET(listenSocket, &readfds);
        for (int i = 0; i < Connections.size(); i++) {
            FD_SET(Connections[i], &readfds);
        }
        select(0, &readfds, 0, 0, 0);
        if (FD_ISSET(listenSocket, &readfds)) {
            SOCKET newConnection = accept(listenSocket, NULL, NULL);
            if (newConnection != INVALID_SOCKET) {
                std::cout << "new connection! N: " << (Connections.size() + 1) << std::endl;
                Connections.push_back(newConnection);
            }
        }
        for (int i = 0; i < Connections.size(); i++) {
            if (FD_ISSET(Connections[i], &readfds)) {
                char buffer[1024];
                int recvret = recv(Connections[i], buffer, 1024, 0);
                if (recvret == SOCKET_ERROR || recvret == 0) {
                    if (WSAGetLastError() == WSAEWOULDBLOCK || recvret == 0) {
                        std::cout << "Lost connection :(" << std::endl;
                        closesocket(Connections[i]);
                        continue;
                    }
                }
                if (recvret > 0) {
                    std::cout << "Got data from connection" << std::endl;
                    char buf[] = "";
                    send(Connections[i], buf, 4, 0);
                }
            }
        }
    }
}