[prog] Re: learning c

[Alice Moomlyn]

<alice>
Thankyou for replying!
</alice>

<almut>
BTW, upon first running your orignal version, I got,
for example

  Enter a string of any length: 
  Alice Moomlyn
  
  This is the string you entered:
  Alice Moomlyn
  
  Reversed using array notation:
  ylmooM ecilA
  
  Reversed using pointer notation:
  ylmooM ecilA

(Note that in the reversed string, the 'n' from
Moomlyn is missing...)
</almut>

<alice>
Whoops!

Just goes to show that I wasn't doing proper testing!

At first the 'reverse' was working but the reading in
of long strings wasn't, so I kinda went around
changing things at random (I know that's not what
you're supposed to do :P) until the input was working,
and then I did all my tests on really long strings of
largely repetitive characters, like this:
 
"ddddddddddddddddddddddddddddddddddddddkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkfffffffffffffffffffffffffffffffffffffffjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj"

so that must be why I didn't realize that the last
letter was being chopped off :P

Anyway, I think I've fixed it now.
</alice>


<almut> 
> A purely syntactic issue:
> 
> Only statements need to be terminated by semicolons,
> not the control
> structure elements like the {}-blocks used for
> grouping statements
> (as usually used in combination with if/else, while,
> for, function
> definitions, etc.).  I.e. it suffices to write
> 
>   while (cond) {
>     statement;
>     statement;
>   }
>   nextstatement;
>
</almut>

<alice>
Ahh...yes. I think I'd kind of half-noticed that the
compiler didn't report errors when I forgot the ;
after code blocks but was still putting them in to be
on the safe side. Thanks for pointing that out!
</alice>

<almut>
This is a very neat program for locating all sorts of
memory-related
errors, like accessing undefined variables, memory
outside of allocated
buffers, and much more.  To be able to do that, it
runs the program in
a CPU emulated by software. Sounds complex? It is, but
it works rather
well.  More info at http://valgrind.kde.org/
If you want to keep programming in C(++), do yourself
a real favor - go
and get it now!
</almut>

<alice>
Will do. 
</alice>

<almut>
Always come
up with test cases which are maximally "nasty" to the
program, i.e. use
sizes exactly matching internal buffersizes (or
multiples thereof), or
buffersize-/+1, or any other magic value which is
brought into
existence by way of the various constants you put in
your code -- you
get the idea...
</almut>

<alice>
I think so...
</alice>

<almut>
P.S. a final meta comment:  in order to get more
feedback here (and
elsewhere), try to pose _specific_ questions, or point
at certain
errors you encountered. For example, you could have
asked "why does
the first character of the reversed string get lost?".
I bet you'd
have gotten at least 5 responses on that one. Very
general requests
for feedback tend to offer a low incentive for the
time-stressed geek.
At least _I_ feel more inclined to respond, when
there's something
catchy, and it looks like I can find out and answer it
in a reasonable
amount of time. Could be that I'm not the only chick
feeling that way.
</almut>

<alice>
To be honest I hadn't even noticed that the last
letter was being chopped off :P I was more looking for
general feedback on coding style etc...

I want to get off to a good start with c, not fall
into bad habits right from the beginning.

I've rewritten the whole thing, breaking it up into 4
files:

1. STRio.h (string input-output header)
http://rafb.net/paste/results/R1575136.html

2. STRio.c (string input-output implementation)
http://rafb.net/paste/results/Fqx42015.html

3. STRmanip.h (string manipulation header)
http://rafb.net/paste/results/m3064945.html

4. STRmanip.c (string manipulation implementation)
http://rafb.net/paste/results/Ux460433.html

If anybody has time to take another look at it and
make any additional comments, that would be great. But
if you're all to busy, that's okay. I understand.
</alice>


=====
"the only way to learn how to be clever is to say stupid things" - anon

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