C++ socket client to python server no connection created

Question

I am trying to create C++ socket client for python server. Because I am new to C++ before creating the C++ client I checked if the python socket server with python client. After creating and running the C++ client the server do not get any connection

server.py

def start_listener():
    ip = "0.0.0.0"
    port = 4444
    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    try:
        # Tying to bind
        server.bind((ip, port))
        server.listen(3)
        print("[+] Server bind on %s:%d" %(ip,port))
    except socket.error as error:
        print("[!] Unable to bind on %s:%d" %(ip,port))

    # Waiting for connections and handle them
    while True:
            print("Wating for connections...")
            # Waiting part
            connenction, addr = server.accept()
            print("[+] Accecpted connection from %s:%d" % (addr[0],addr[1]))
            data = connenction.recv(2000).decode()
            print(data)

start_listener()

ClientSocket.cpp:

#include "ClientSocket.h"
#include <iostream>

ClientSocket::ClientSocket(string ip, int port) {
    socket_ip = ip;
    socket_port = port;
}

void ClientSocket::CreateSession(){
    ClientSocket::sock = socket(AF_INET, SOCK_STREAM, 0);
    if(ClientSocket::sock < 0){
        cout << "[!] Unable to create socket" << endl;
    }
    struct sockaddr_in serv_addr;
    serv_addr.sin_family = AF_INET; 
    serv_addr.sin_addr.s_addr = inet_addr((ClientSocket::socket_ip).c_str());
    serv_addr.sin_port = htons(ClientSocket::socket_port);

    if(connect(ClientSocket::sock, (SOCKADDR *)&serv_addr ,sizeof(sockaddr)) < 0){
        cout << "[!] Unable to connect to remote socket" << endl;
    }
}

ClientSocket.h

#include <string>
#include <list>
#include <winsock2.h>
#include <Ws2tcpip.h>

using namespace std;

#ifndef SOCKET_H
#define SOCKET_H

class ClientSocket {
    private:
        string socket_ip;
        int socket_port;
        SOCKET sock;
    public:
        ClientSocket(string ip, int port);
        void PrintSocket();
        void CreateSession();
        void SendData(string data);
};

#endif // SOCKET_H

main.cpp

#include "ClientSocket.h"

using namespace std;

int main() {
    ClientSocket clientsocket ("127.0.0.1", 4444);
    clientsocket.CreateSession();
    return 0;
}

output

[!] Unable to connect to remote socket

After including <errno.h> and print the error its print no error

Answer 1

Add

WSADATA wsaData;
WSAStartup(MAKEWORD(2, 0), &wsaData);

before creating the client socket to initialize winsock2

So it should look like this:

void CreateSession() {
    WSADATA wsaData;
    WSAStartup(MAKEWORD(2, 0), &wsaData);
    this->sock = socket(AF_INET, SOCK_STREAM, 0);

    if (this->sock < 0) {
        cout << "[!] Unable to create socket" << endl;
    }
        struct sockaddr_in serv_addr;
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = inet_addr((ClientSocket::socket_ip).c_str());
    serv_addr.sin_port = htons(ClientSocket::socket_port);

    if (connect(this->sock, (SOCKADDR*)&serv_addr, sizeof(sockaddr)) == SOCKET_ERROR) {
        cout << "[!] Unable to connect to remote socket" << endl;
    }
}