CS 120 / Lab 3 - Feb 18 and 19, 2010
Allison Mankin, amankin1@jhu.edu

1. review man and man -k

   useful site:  http://www.oreillynet.com/linux/cmd/

2. review simple Makefile - discussion with test-splint.c below

3. tar and gzip
   c create
   v verbose
   f output file
   t show table of contents
   x extract

   tar cvf <tarfile>.tar <directoryorfilename>
   tar czf <tarfile>.tar.gz <directoryfilename>
   tar tvf <tarfilename>.tar 
   tar xvf <tarfilename>.tar
   tar xzf <tarfilename>.tar.gz (or .tgz)
   instead of using z in tar, can use gzip/gunzip - see man

   Exercise: make a gzipped tar file containing the
   a copy of your ~/tmp folder, named tmp.tar.gz
   
4. splint - discussion with test-splint.c below

5. diff - diff two files - your choice of a program and your
   choice of a program with any change edited in.  Explain
   how to interpret the output - discussion with using 
   test-splint.c and test.c, code before inserting bug to
   exercise splint.  use redirection of stdout

   what's a good use for '>>'?  
   discuss diff, > and >> wrt to assignment p2 (?)

6. several new emacs capabilities to try at home:

mark a region	ctrl-spacebar then cursor down or up
cut a region    ctrl-w
paste a region	ctrl-y
undo		ctrl-x-u


============================================
model Makefile: 

     CFLAGS= -ansi -pedantic -Wall -Wextra -std=c99 -O
     CC=gcc

     test: test.c
     test-splint: test-splint.c
     yourprog: yourprog.c

============================================
compilation in emacs (review)
esc-x compile - respond in command buffer either:
  make yourprog, or
  make -f alternativeMakefilename yourprog
============================================
example code:

/*
 * test.c - extract exactly 10 digit
 * phone numbers from any format. Returns
 * error if other than 10 digits found.
 * test-splint.c - has an error for splint.
 */

#include <stdio.h>
#include <ctype.h>
#include <string.h>

#define LINELEN 80

int main ()
{
  int input[LINELEN];
  int i, int digits;
 
  printf("enter 10-digit phone number in any format\n")

  /* 
   fgets needs a char array, not int. Both 
   the compiler and the program react, so
   splint isn't the only line of defense. 
   However, if this were a method of my own, 
   vs. a C library function, splint could
   be alone in giving the flag.
  */
    
  fgets(input, LINELEN, stdin);
  digits = 0;

  for (i=0; i<LINELEN ; i++) 
    {
      if (isdigit(input[i])) {
      printf("%c", input[i]);
      digits++;
    }
  }
  if (digits == 10) 
    printf (":  phone number input\n");
  else
    printf (": incorrect entry of %2d digits\n", digits);
  return 0;
}

============================================
example of using 'diff'

tcsh$ diff test.c test-splint.c > diffprograms
tcsh$ less diffprograms
4a5
>  * test-splint.c - has an error for splint.
6d6
< 
15,16c15,17
<   char input[LINELEN];
<   int i, digits;
---
>   int input[LINELEN];
>   int i;
>   int digits;
18a20,28
> 
>   /* 
>    fgets should have char array, not int.
>    Both the compiler and my program react to
>    it, so splint is not crucial.  However if
>    this were a method of my own, rather than
>    a C function, it might be only splint
>    catching this type mismatch.
>   */