How do I make simple chatbot using Sockets in the C language with system calls. Wlhen running the cient will ask a question; the server will reply with an answer which has been predetermined by us. We need to have 5 different answers for 5 different questions. I have been provided with some sample code for Client and Server sockets which I have included below:

Socket_Client.c contains: /*C ECHO client example using sockets*/

#include #include #include #include int main(int argc , char *argv[]) { int sock; struct sockaddr_in server; char message[1000] , server_reply[2000]; //Create socket sock = socket(AF_INET , SOCK_STREAM , 0); if (sock == -1) { printf("Could not create socket"); } puts("Socket created"); server.sin_addr.s_addr = inet_addr("127.0.0.1"); server.sin_family = AF_INET; server.sin_port = htons( 8888 ); //Connect to remote server if (connect(sock , (struct sockaddr *)&server , sizeof(server)) < 0) { perror("connect failed. Error"); return 1; } puts("Connected "); //keep communicating with server while(1) { printf("Enter message : "); scanf("%s" , message); //Send some data if( send(sock , message , strlen(message) , 0) < 0) { puts("Send failed"); return 1; } //Receive a reply from the server if( recv(sock , server_reply , 2000 , 0) < 0) { puts("recv failed"); break; } puts("Server reply :"); puts(server_reply); } //close(sock); return 0; }

Socket_Server.c contains:

#include #include #include #include #include //inet_addr #include //write #include //for threading //the thread function void *connection_handler(void *); int main(int argc , char *argv[]) { int socket_desc , client_sock , c , *new_sock; struct sockaddr_in server , client; //Create socket socket_desc = socket(AF_INET , SOCK_STREAM , 0); if (socket_desc == -1) { printf("Could not create socket"); } puts("Socket created"); //Prepare the sockaddr_in structure server.sin_family = AF_INET; server.sin_addr.s_addr = INADDR_ANY; server.sin_port = htons( 8888 ); //Bind if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0) { //print the error message perror("bind failed. Error"); return 1; } puts("bind done"); //Listen listen(socket_desc , 3); //Accept and incoming connection puts("Waiting for incoming connections..."); c = sizeof(struct sockaddr_in); //Accept and incoming connection puts("Waiting for incoming connections..."); c = sizeof(struct sockaddr_in); while( (client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)) ) { puts("Connection accepted"); pthread_t sniffer_thread; new_sock = malloc(1); *new_sock = client_sock; if( pthread_create( &sniffer_thread , NULL , connection_handler , (void*) new_sock) < 0) { perror("could not create thread"); return 1; } //Now join the thread , so that we dont terminate before the thread //pthread_join( sniffer_thread , NULL); puts("Handler assigned"); } if (client_sock < 0) { perror("accept failed"); return 1; } return 0; } /* * This will handle connection for each client * */ void *connection_handler(void *socket_desc) { //Get the socket descriptor int sock = *(int*)socket_desc; int read_size; char *message , client_message[2000]; //Send some messages to the client message = "Greetings! I am your connection handler "; write(sock , message , strlen(message)); message = "Now type something and i shall repeat what you type "; write(sock , message , strlen(message)); //Receive a message from client while( (read_size = recv(sock , client_message , 2000 , 0)) > 0 ) { //Send the message back to client write(sock , client_message , strlen(client_message)); } if(read_size == 0) { puts("Client disconnected"); fflush(stdout); } else if(read_size == -1) { perror("recv failed"); } //Free the socket pointer free(socket_desc); return 0; }