C++ Simple Chat Program In a Console Window (Winsock & Multithreading)

[Jacob Roman]

I made a simple chat program using a console window where you run the server in one program, and multiple clients in another, where the clients can chit chat with each other, even from different machines if you got the right port and IP address handy. You could quite possibly squeeze this into an MMO game or just about anything, Enjoy the code

Server:

#include <iostream>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <string>
#include <thread>
#include <vector>
 
#pragma comment (lib, "Ws2_32.lib")
 
#define IP_ADDRESS "192.168.56.1"
#define DEFAULT_PORT "3504"
#define DEFAULT_BUFLEN 512
 
struct client_type
{
    int id;
    SOCKET socket;
};
 
const char OPTION_VALUE = 1;
const int MAX_CLIENTS = 5;
 
//Function Prototypes
int process_client(client_type &new_client, std::vector<client_type> &client_array, std::thread &thread);
int main();
 
int process_client(client_type &new_client, std::vector<client_type> &client_array, std::thread &thread)
{
    std::string msg = "";
    char tempmsg[DEFAULT_BUFLEN] = "";
 
    //Session
    while (1)
    {
        memset(tempmsg, 0, DEFAULT_BUFLEN);
 
        if (new_client.socket != 0)
        {
            int iResult = recv(new_client.socket, tempmsg, DEFAULT_BUFLEN, 0);
 
            if (iResult != SOCKET_ERROR)
            {
                if (strcmp("", tempmsg))
                    msg = "Client #" + std::to_string(new_client.id) + ": " + tempmsg;
 
                std::cout << msg.c_str() << std::endl;
 
                //Broadcast that message to the other clients
                for (int i = 0; i < MAX_CLIENTS; i++)
                {
                    if (client_array[i].socket != INVALID_SOCKET)
                        if (new_client.id != i)
                            iResult = send(client_array[i].socket, msg.c_str(), strlen(msg.c_str()), 0);
                }
            }
            else
            {
                msg = "Client #" + std::to_string(new_client.id) + " Disconnected";
 
                std::cout << msg << std::endl;
 
                closesocket(new_client.socket);
                closesocket(client_array[new_client.id].socket);
                client_array[new_client.id].socket = INVALID_SOCKET;
 
                //Broadcast the disconnection message to the other clients
                for (int i = 0; i < MAX_CLIENTS; i++)
                {
                    if (client_array[i].socket != INVALID_SOCKET)
                        iResult = send(client_array[i].socket, msg.c_str(), strlen(msg.c_str()), 0);
                }
 
                break;
            }
        }
    } //end while
 
    thread.detach();
 
    return 0;
}
 
int main()
{
    WSADATA wsaData;
    struct addrinfo hints;
    struct addrinfo *server = NULL;
    SOCKET server_socket = INVALID_SOCKET;
    std::string msg = "";
    std::vector<client_type> client(MAX_CLIENTS);
    int num_clients = 0;
    int temp_id = -1;
    std::thread my_thread[MAX_CLIENTS];
 
    //Initialize Winsock
    std::cout << "Intializing Winsock..." << std::endl;
    WSAStartup(MAKEWORD(2, 2), &wsaData);
 
    //Setup hints
    ZeroMemory(&hints, sizeof(hints));
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
    hints.ai_flags = AI_PASSIVE;
 
    //Setup Server
    std::cout << "Setting up server..." << std::endl;
    getaddrinfo(static_cast<LPCTSTR>(IP_ADDRESS), DEFAULT_PORT, &hints, &server);
 
    //Create a listening socket for connecting to server
    std::cout << "Creating server socket..." << std::endl;
    server_socket = socket(server->ai_family, server->ai_socktype, server->ai_protocol);
 
    //Setup socket options
    setsockopt(server_socket, SOL_SOCKET, SO_REUSEADDR, &OPTION_VALUE, sizeof(int)); //Make it possible to re-bind to a port that was used within the last 2 minutes
    setsockopt(server_socket, IPPROTO_TCP, TCP_NODELAY, &OPTION_VALUE, sizeof(int)); //Used for interactive programs
 
    //Assign an address to the server socket.
    std::cout << "Binding socket..." << std::endl;
    bind(server_socket, server->ai_addr, (int)server->ai_addrlen);
 
    //Listen for incoming connections.
    std::cout << "Listening..." << std::endl;
    listen(server_socket, SOMAXCONN);
 
    //Initialize the client list
    for (int i = 0; i < MAX_CLIENTS; i++)
    {
        client[i] = { -1, INVALID_SOCKET };
    }
 
    while (1)
    {
 
        SOCKET incoming = INVALID_SOCKET;
        incoming = accept(server_socket, NULL, NULL);
 
        if (incoming == INVALID_SOCKET) continue;
 
        //Reset the number of clients
        num_clients = -1;
 
        //Create a temporary id for the next client
        temp_id = -1;
        for (int i = 0; i < MAX_CLIENTS; i++)
        {
            if (client[i].socket == INVALID_SOCKET && temp_id == -1)
            {
                client[i].socket = incoming;
                client[i].id = i;
                temp_id = i;
            }
 
            if (client[i].socket != INVALID_SOCKET)
                num_clients++;
 
            //std::cout << client[i].socket << std::endl;
        }
 
        if (temp_id != -1)
        {
            //Send the id to that client
            std::cout << "Client #" << client[temp_id].id << " Accepted" << std::endl;
            msg = std::to_string(client[temp_id].id);
            send(client[temp_id].socket, msg.c_str(), strlen(msg.c_str()), 0);
 
            //Create a thread process for that client
            my_thread[temp_id] = std::thread(process_client, std::ref(client[temp_id]), std::ref(client), std::ref(my_thread[temp_id]));
        }
        else
        {
            msg = "Server is full";
            send(incoming, msg.c_str(), strlen(msg.c_str()), 0);
            std::cout << msg << std::endl;
        }
    } //end while
 
 
    //Close listening socket
    closesocket(server_socket);
 
    //Close client socket
    for (int i = 0; i < MAX_CLIENTS; i++)
    {
        my_thread[i].detach();
        closesocket(client[i].socket);
    }
 
    //Clean up Winsock
    WSACleanup();
    std::cout << "Program has ended successfully" << std::endl;
 
    system("pause");
    return 0;
}

Client:

#include <winsock2.h>
#include <ws2tcpip.h>
#include <iostream>
#include <string>
#include <thread>
 
using namespace std;
 
#pragma comment (lib, "Ws2_32.lib")
 
#define DEFAULT_BUFLEN 512            
#define IP_ADDRESS "192.168.56.1"
#define DEFAULT_PORT "3504"
 
struct client_type
{
    SOCKET socket;
    int id;
    char received_message[DEFAULT_BUFLEN];
};
 
int process_client(client_type &new_client);
int main();
 
int process_client(client_type &new_client)
{
    while (1)
    {
        memset(new_client.received_message, 0, DEFAULT_BUFLEN);
 
        if (new_client.socket != 0)
        {
            int iResult = recv(new_client.socket, new_client.received_message, DEFAULT_BUFLEN, 0);
 
            if (iResult != SOCKET_ERROR)
                cout << new_client.received_message << endl;
            else
            {
                cout << "recv() failed: " << WSAGetLastError() << endl;
                break;
            }
        }
    }
 
    if (WSAGetLastError() == WSAECONNRESET)
        cout << "The server has disconnected" << endl;
 
    return 0;
}
 
int main()
{
    WSAData wsa_data;
    struct addrinfo *result = NULL, *ptr = NULL, hints;
    string sent_message = "";
    client_type client = { INVALID_SOCKET, -1, "" };
    int iResult = 0;
    string message;
 
    cout << "Starting Client...\n";
 
    // Initialize Winsock
    iResult = WSAStartup(MAKEWORD(2, 2), &wsa_data);
    if (iResult != 0) {
        cout << "WSAStartup() failed with error: " << iResult << endl;
        return 1;
    }
 
    ZeroMemory(&hints, sizeof(hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
 
    cout << "Connecting...\n";
 
    // Resolve the server address and port
    iResult = getaddrinfo(static_cast<LPCTSTR>(IP_ADDRESS), DEFAULT_PORT, &hints, &result);
    if (iResult != 0) {
        cout << "getaddrinfo() failed with error: " << iResult << endl;
        WSACleanup();
        system("pause");
        return 1;
    }
 
    // Attempt to connect to an address until one succeeds
    for (ptr = result; ptr != NULL; ptr = ptr->ai_next) {
 
        // Create a SOCKET for connecting to server
        client.socket = socket(ptr->ai_family, ptr->ai_socktype,
            ptr->ai_protocol);
        if (client.socket == INVALID_SOCKET) {
            cout << "socket() failed with error: " << WSAGetLastError() << endl;
            WSACleanup();
            system("pause");
            return 1;
        }
 
        // Connect to server.
        iResult = connect(client.socket, ptr->ai_addr, (int)ptr->ai_addrlen);
        if (iResult == SOCKET_ERROR) {
            closesocket(client.socket);
            client.socket = INVALID_SOCKET;
            continue;
        }
        break;
    }
 
    freeaddrinfo(result);
 
    if (client.socket == INVALID_SOCKET) {
        cout << "Unable to connect to server!" << endl;
        WSACleanup();
        system("pause");
        return 1;
    }
 
    cout << "Successfully Connected" << endl;
 
    //Obtain id from server for this client;
    recv(client.socket, client.received_message, DEFAULT_BUFLEN, 0);
    message = client.received_message;
 
    if (message != "Server is full")
    {
        client.id = atoi(client.received_message);
 
        thread my_thread(process_client, client);
 
        while (1)
        {
            getline(cin, sent_message);
            iResult = send(client.socket, sent_message.c_str(), strlen(sent_message.c_str()), 0);
 
            if (iResult <= 0)
            {
                cout << "send() failed: " << WSAGetLastError() << endl;
                break;
            }
        }
 
        //Shutdown the connection since no more data will be sent
        my_thread.detach();
    }
    else
        cout << client.received_message << endl;
 
    cout << "Shutting down socket..." << endl;
    iResult = shutdown(client.socket, SD_SEND);
    if (iResult == SOCKET_ERROR) {
        cout << "shutdown() failed with error: " << WSAGetLastError() << endl;
        closesocket(client.socket);
        WSACleanup();
        system("pause");
        return 1;
    }
 
    closesocket(client.socket);
    WSACleanup();
    system("pause");
    return 0;
}

[thunduaga]

Hi, for the following lines i get compile errors

in the server:

//Create a thread process for that client
my_thread[temp_id] = std::thread(process_client, std::ref(client[temp_id]), std::ref(client), std::ref(my_thread[temp_id]));

in the client:

thread my_thread(process_client, client);

VS is telling me that there are no constructors matching these arguments or even this number of arguments. Could you please explain a little bit about creating these threads? is process_client the thread proc? i have some experience with win32, multithreading and thread syncronization but never networking and i dont remember using std::thread ever

[tounsi8orr]

i compile it with out any error, thanks for share

[lafumafin]

i compile it with out any error, thanks for share

Where did you got the librarys, the header files?

server.cpp:2:22: fatal error: winsock2.h: Datei oder Verzeichnis nicht gefunden
compilation terminated.
client.cpp:1:22: fatal error: winsock2.h: Datei oder Verzeichnis nicht gefunden
compilation terminated.
winsock2.h:21:22: fatal error: pshpack4.h: Datei oder Verzeichnis nicht gefunden
compilation terminated.

[tayyabayounas]

Where did you got the librarys, the header files?

server.cpp:2:22: fatal error: winsock2.h: Datei oder Verzeichnis nicht gefunden
compilation terminated.
client.cpp:1:22: fatal error: winsock2.h: Datei oder Verzeichnis nicht gefunden
compilation terminated.
winsock2.h:21:22: fatal error: pshpack4.h: Datei oder Verzeichnis nicht gefunden
compilation terminated.

i m using visual studio 2013 ..... plz tell me where to compile that program...can i compile it in visualstudio win32 console application or any other:confused

[Jacob Roman]

Try installing the latest version of Windows SDK if it didnt come with your version of visual studio.

[errno]

Hi Jacob,

thank you so much this sample. That's great..

Best regards

[petrdruker]

Have the same issue... How did you solve it?

[noblemaks]

Hi, for the following lines i get compile errors

in the server:

//Create a thread process for that client
my_thread[temp_id] = std::thread(process_client, std::ref(client[temp_id]), std::ref(client), std::ref(my_thread[temp_id]));

in the client:

thread my_thread(process_client, client);

VS is telling me that there are no constructors matching these arguments or even this number of arguments. Could you please explain a little bit about creating these threads? is process_client the thread proc? i have some experience with win32, multithreading and thread syncronization but never networking and i dont remember using std::thread ever

If you use VS 2017 the server part will compile well, but in the client you would need to change
thread my_thread(process_client, client);
to
thread my_thread(process_client, ref(client));