-------------------------------------
Programming suggestions for Lab #02
-------------------------------------
-Ian! D. Allen - idallen@idallen.ca

Here are some comments that will help you fix your code to work correctly
and earn full marks in future assignments.

You can't have a working Lab #3 until you have a working Lab #2.
You have to live with your own code.

This note file is full of wrong examples, not good code.

- missing comments on the code you added
  - if you write code - comment it (see notes file programming_style.txt)
  - if you use raw code from other people - comment it
  - future assignments: no comments, no marks

- also comment what the code does, not just what the assignment wants:

 /* The code was modified for the purposes of this assignment */

- use the exact file names given in the lab exercise
  - if the lab says to use a particular set of names to the cstsubmit
    command, you have to use those names or else my marking-assist
    scripts won't find your files for marking

- if you copy code from other people, make sure it works:
  - sendall.c has an uninitialized variable error if passed a zero length
  - gcc warnings would have told you this

- read your gcc warnings and fix them
  - several people have broken linked list implementations
  - use valgrind

- get EOF handling right in your client
  - see notes file: eof_handling.txt
  - don't print a line when you get EOF - there is nothing there
  - watch out for lack of \0 on buffers

                n = read(sockfd,buffer,255); /* read from socket */
                if (n < 0) {
                   kill(chid,SIGTERM); /* kill child to prevent zombie */
                   error("ERROR reading from socket");
                   return 0; /* return on read error */
                }
                printf("\n%s\n",buffer);

- don't write useless comments (see notes file programming_style.txt)

      // bind
      // listen
      int sendall(int s, char *buf, int *len); /* declare prototype */
      chid = fork(); /* split to two processes */
      n = read(sockfd,buffer,255); /* read from socket */

- don't use magic numbers; #define them or use sizeof()
  - related numbers should relate in your code
  - make it hard for a change in size to break your code

          char buffer[256];
          bzero(buffer,256);
          n = read(sockfd,buffer,255); /* read from socket */

- don't use "else" after return/exit
- and use argv[0] for program name, not compiled-in name

          if(argc != 2)
              error("Usage: ./chat [port]\n");
          else
              port = atoi(argv[1]);

- don't write garbage bytes to your clients
  - if you read nbytes, only write nbytes

       nbytes = read(..., buf, ...
       if (sendall(newfd, buf, sizeof(buf)) == -1) ...

- don't overflow your buffers; use snprintf() not sprintf()

     char buf[256];
     char buf2[256];
     nbytes = sprintf(buf2,"%s:%d: %.*s", ips[i], i, nbytes, buf);

- don't overflow or underflow your buffers
  - don't index with a bad number (-1) or go beyond (nbytes)

     nbytes = read(..., buf, sizeof(buf)
     buf[nbytes] = '\0';

- if you use command line arguments, check for the right number
  - make sure the number of arguments exactly matches what you expect
  - don't simply check for argc >= 2 - check that argc == 2
  - never ignore user command line input

- no inconsistent indentation style
  - correct indentation is essential; unreadable code won't be marked
  - Unix tab stops are every 8 spaces; your submitted code must match
  - "man expand"