what is this code chunk doing
// Set the IP and port of the server to connect to.
struct sockaddr_in server;
server.sin_family = AF_INET;
server.sin_port = htons(PORT);
if (inet_pton(AF_INET, "127.0.0.1", &server.sin_addr) < 1) {
    perror("client: inet_pton");
    close(sock_fd);
    exit(1);
}