String and int concatination

Question

I have to concatenate the output of fgets to an int (clientid), and store this in a char[1024] buffer.

Here's my code:

clientid = rand() % 256;



while(1)
{
    cout<<"Client: Enter Data for Client=";

    fgets(buffer,MAXSIZE-1,stdin);

    if((send(sockfd,buffer,strlen(buffer),0))==-1)
    {
        cout<<"Failure Sending Message";
        close(sockfd);
        exit(1);
    }
    else
    {
        cout<<"Client:Message being sent:"<<buffer;
        num=recv(sockfd,buffer,sizeof(buffer),0);
        if(num<=0)
        {
            cout<<"either connection close or Error";
            break;
        }
        buffer[num]='\0';
        cout<<"Client:message received from Server:"<<buffer<<endl;
    }
}

close(sockfd);
return 0;

How can I extract the clientid from the message on the server side?

Answer 1

You can add it to the beginning of the buffer itself. For example if your clientid is 123 then you can send "123:Message" where ":" can act as a separator. This means you should be reading those many numbers ahead in buffer, instead of from the beginning.

snprintf (buffer, sizeof(buffer), "%d:", clientid); // Add the clientid at the beginning before reading 
fgets(buffer + strlen (buffer),MAXSIZE-1,stdin);// Move by the len of buffer which contains clientid