std::cout << "Server started !" << std::endl;

std::fstream cfile;

cfile.open("server.config");

if (!cfile.is_open()) {

std::cout << "error open the config file ." << std::endl;

exit(0);

}

std::map<std::string, std::string> config;

std::string line;

while (getline(cfile, line)) {

if (line.rfind("#", 0) == 0)

continue;

int epos = line.find("=");

config.insert(std::pair<std::string, std::string>(line.substr(0, epos), line.substr(epos + 1, line.length())));

}

cfile.close();

std::cout << "finished read the config file ." << std::endl;

int it_port = atoi(config["port"].c_str());

// create hte socket .

int socket_desc = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

struct sockaddr_in socket_address;

memset(&socket_address, 0, sizeof(struct sockaddr_in));

socket_address.sin_family = AF_INET;

socket_address.sin_port = htons(it_port);

socket_address.sin_addr.s_addr = INADDR_ANY;

if (bind(socket_desc, (struct sockaddr *) &socket_address, sizeof(socket_address)) != 0) {

std::cout << "Failed to bind to the address!" << std::endl;

exit(0);

}

if (listen(socket_desc, SOMAXCONN) != 0) {

std::cout << "Failed to put the socket in a listening state" << std::endl;

exit(0);

}

// start the loop to accept the request;

int accept_status;

sockaddr_in socket_accept;

int run_loop = 1;

while (run_loop) {

std::cout << "wait for next connection ." << std::endl;

int address_size = sizeof(address_size);

memset(&socket_accept, 0, address_size);

accept_status = accept(socket_desc, (sockaddr *) &socket_accept, (socklen_t *) &address_size);

fcntl(accept_status, F_SETFL, O_NONBLOCK);

if (INVALID_SOCKET == accept_status) {

exit(0);

} else {

std::cout << "client accept !" << std::endl;

std::string response = "hello, world!";

send(socket_desc, response.data(), response.length(), 0);

}

close(accept_status);

}

// end the loop;

shutdown(socket_desc, SHUT_RDWR);

close(socket_desc);

std::cout << "socket server closed ." << std::endl;

return 0;

}