Pascal - C (2)

[Ruud]

Hallo allemaal,
During the conversion of my program from Pascal to C, I was more or
less able to find the C equivalent of most Pascal functions so far.
Only four gave me some real trouble. I solved them but it could be I
overlooked something.

1) In Pascal you can declare functions inside a function. AFAIK this
is not possible with C. Or am I wrong?

2) In Pascal there exists the "in" function. Example:

if (c in ['A'..'F', '0'..'9']) then { c is hexadecimal }

This can be translated like:

if ( ((c >= 'A') && (c <= 'Z'))
|| ((c >= '0') && (c <= '9'))) .... // c is hexadecimal

I just wonder if there is a more simpler solution.

3) In Pascal I can "add" lines:

Line1 = 'File size:' + sSize + ' bytes.';

My solution:

strcpy(Line1, "File size:");
strcat(Line1, sSize);
strcat(Line1, " bytes.);

Again, I just wonder if there is a more simpler solution.

4) In Pascal I can "add" just one character of another string:

Str1 = Str2 + Str3[5];

Unfortunately strcat(Str1, Str3[5]); doesn't work, I get an error
message. My solution:

Str4[0] = Str3[5];
Str4[1] = 0;
strcpy(Str1, Str2};
strcat(Str1, Str4};

It works but in this case I'm certainly not happy with the solution.
Is there a better way?

Many thanks for any comment!
--
___
/ __|__
/ / |_/ Groetjes, Ruud Baltissen
\ \__|_\
\___| http://Ruud.C64.org

[CBFalconer]

dj******@csclub .uwaterloo.ca.i nvalid wrote:

Eric Sosman <es*****@ieee-dot-org.invalidwrot e:

.... snip ...

>

>... and now you need to tack on the terminating '\0'
that strncat() didn't give you.

It's strncpy that doesn't give a terminating '\0'; strncat copies
at most count characters from the source string to the end of the
dest string and then adds a '\0'. (I *did* say that it was
confusing. I had to check the man page to see which strncat was.
I just checked N1124, and it agrees with the man page (7.21.3.2).)

I suggest ignoring strncpy and its nuisances, and using strlcpy and
strlcat. These names are reserved, but you can change them.
Source code in standard C, and full documentation, are all
available at:

<http://cbfalconer.home .att.net/download/strlcpy.zip>

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home .att.net>
Try the download section.

[dj3vande]

In article <49************ ***@yahoo.com>,
CBFalconer <cb********@mai neline.netwrote :

>I suggest ignoring strncpy and its nuisances, and using strlcpy and
strlcat.

The case I was commenting on was one of the (admittedly few) cases
where strncat makes it *easier* to do The Right Thing than strlcat
would.
dave

--
Dave Vandervies dj3vande at eskimo dot com
Actually, I'm toying with approaching a mug-printing outfit to see if they can
do me an Emacs reference quart-sized mug although I fear that the text might
still be too small to read. --Peter Corlett in the scary devil monastery

[Keith Thompson]

Pilcrow <Pi******@gmail .comwrites:

On Sun, 02 Nov 2008 10:59:20 +1300, Ian Collins <ia******@hotma il.com>
wrote:

>>Ruud wrote:
Sorry, no. One alternative is to use a regular expression library if
you have a lot of these.

Please. Point me to a regular expression library for C. Please.

A Google search for "C regular expression library" gets about 441,000
hits; many of the first few appear to be quite relevant.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[s0suk3]

On Nov 2, 5:31*pm, CBFalconer <cb********@yah oo.comwrote:

dj******@csclub .uwaterloo.ca.i nvalid wrote:

Eric Sosman *<es*****@ieee-dot-org.invalidwrot e:

... snip ...

... and now you need to tack on the terminating '\0'
that strncat() didn't give you.

It's strncpy that doesn't give a terminating '\0'; strncat copies
at most count characters from the source string to the end of the
dest string and then adds a '\0'. *(I *did* say that it was
confusing. *I had to check the man page to see which strncat was.
I just checked N1124, and it agrees with the man page (7.21.3.2).)

I suggest ignoring strncpy and its nuisances, and using strlcpy and
strlcat. *These names are reserved, but you can change them.
Source code in standard C, and full documentation, are all
available at:

* <http://cbfalconer.home .att.net/download/strlcpy.zip>

So you bash powerful functions like asprintf(), but advocate trivial,
ten-liner functions like strlcpy() and strlcat()?

Sebastian

[Nick Keighley]

On 2 Nov, 12:11, Ruud <Ruud.Baltis... @apg.nlwrote:

jacob navia wrote:

If you do not know enough C please do not use this group.

Then please be a good man and tell me what level I should have before
I can attend this group?

Jacob was talking rubbish

Chuck wrote:

<snip>

A good book, such as K&R II, would be helpful.

The book isn't the problem, see next.

Richard wrote:

Ruud, you use an odd quoting convention doesn't your
news software support the more usual conventions
(all the attributions at the top)?

Why not at least tell him about:

if(isupper(c) || isdigit(c))

and

if(strchr("ABCD EFGHIJKLMNOPQRS TUVWXYZ01234567 89", c) != NULL)

The problem is not knowing all those available functions.

yes, I remember all those functions and headers looked pretty
forbidding when I started learning C (also from pascal).
It didn't help that my implementation didn't distinguish
non-standard from standard headers.

And knowing
another language is a disavantage as well: instead of reading the book
line by line, one tends to look just at "how is this done in C".

K&R is pretty good for getting C idioms over. It really is
worth ploughing through K&R and doing the exercises. It's
not a big book (though information dense).

And even reading the book line by line isn't a guarantee for success:

there are no guarantees!

I justed searched the book "C in 21 days"

"xyz in small number days" isn't usually a promising title.
Really, give K&R a try.

I've got a book that promises to teach me to ride a horse in
a weekend...

for 'isdigit' and only found
one source file using this function. OTOH, this source file also
mentioned the function 'isspace' and this function does exactly what
one of my own made function does; detecting white space.

sprintf

Not mentioned at all "C in 21 days"

oh dear. sprintf() is *really* useful.

:( Because 'printf' was well
explained, I never used the help function of Borland C to give it a
better look. I wish I had because I just did: I learned nothing new
about 'printf' but the page also mentioned 'sprintf' and many more
other functions.

Trent wrote:

strncat(Str1, &Str3[5], 1);

Here I have no excuse, it is mentioned very clearly in the book.

--
Nick Keighley

"ALGOL 60 was a language so far ahead of its time that it
was not only an improvement on its predecessors but also
on nearly all its successors".
--C.A.R. Hoare

[Nick Keighley]

On 2 Nov, 22:08, Eric Sosman <[e-mail] e:

dj3va...@csclub .uwaterloo.ca.i nvalid wrote:

In article <gekuc2$at...@r egistered.motza rella.org>,
Eric Sosman *<[e-mail] e:

dj3va...@csclub .uwaterloo.ca.i nvalid wrote:

>[Copying a single character into a string]

>This is also a case where strncat's (generally confusing)
interpretati on of its count argument turns out to be useful:
* * strcpy(Str1,Str 2);
* * strncat(Str1,St r3+5,1);
(But be careful using this one in code that has to be maintained.)

* * ... and now you need to tack on the terminating '\0'
that strncat() didn't give you.

It's strncpy that doesn't give a terminating '\0'; strncat copies at
most count characters from the source string to the end of the dest
string and then adds a '\0'. *(I *did* say that it was confusing. *I
had to check the man page to see which strncat was. *I just checked
N1124, and it agrees with the man page (7.21.3.2).)

* * *(Sigh.) *Not my day, is it? *I must have forgotten not
to take my stupid pills ...

I have a reflex, as soon as I see a string of the form strn* in a post
I start to post my standard "strncpy() may not do what you expect"
reply. I had it all composed and ready to send when I noticed he
was using strncat(). So I pressed Discard instead of Send.
But it was close :-)
--
Nick Keighley

"Resistance is futile. Read the C-faq."
-- James Hu (c.l.c.)

[Antoninus Twink]

On 3 Nov 2008 at 7:36, s0****@gmail.co m wrote:

On Nov 2, 5:31Â*pm, CBFalconer <cb********@yah oo.comwrote:

>I suggest ignoring strncpy and its nuisances, and using strlcpy and
strlcat. Â*These names are reserved, but you can change them.
Source code in standard C, and full documentation, are all
available at:

Â* <http://[spam snipped]>

So you bash powerful functions like asprintf(), but advocate trivial,
ten-liner functions like strlcpy() and strlcat()?

Yes, funny how that works, isn't it?

I often wonder what motivates CBF to post his spamming crap about
strlcpy, ggets, etc. time and time again. Maybe he makes ad revenue from
his site, or maybe it's just the ego trip of looking at his logs and
counting the number of people he manages to gull into making the mistake
of downloading his unreadable garbage.

[Antoninus Twink]

On 3 Nov 2008 at 8:31, Nick Keighley wrote:

On 2 Nov, 12:11, Ruud <Ruud.Baltis... @apg.nlwrote:

>jacob navia wrote:

If you do not know enough C please do not use this group.

Then please be a good man and tell me what level I should have before
I can attend this group?

Jacob was talking rubbish

No, he wasn't.

He was clearly addressing Collins' arrogance in wading into a
conversation with an air of authority and spouting nonsense. Jacob was
clearly criticizing people who pretend to be C experts while in fact
talking nonsense, not newbies with genuine questions.

[CBFalconer]

s0****@gmail.co m wrote:

CBFalconer <cb********@yah oo.comwrote:

.... snip ...

>

>I suggest ignoring strncpy and its nuisances, and using strlcpy
and strlcat. These names are reserved, but you can change them.
Source code in standard C, and full documentation, are all
available at:

<http://cbfalconer.home .att.net/download/strlcpy.zip>

So you bash powerful functions like asprintf(), but advocate
trivial, ten-liner functions like strlcpy() and strlcat()?

Definitely. Especially functions whose complete action is easily
described. Above all when they replace variadic (and thus error
prone) functions.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home .att.net>
Try the download section.

[robertwessel2]

On Nov 2, 1:17*pm, Eric Sosman <[e-mail] e:

dj3va...@csclub .uwaterloo.ca.i nvalid wrote:

* * * *strcpy(Str1, Str2);
* * * *Str1[ strlen(Str2) ] = Str3[5];
* * * *Str1[ strlen(Str2) ] = '\0';

That last line looks wrong to me; I think you want to add 1 to
strlen(Str2) before you use it as an index into Str1.

* * *Right you are. *Thanks.

Actually you need to save the result of the strlen() in the second
line, since the assignment in the second line will eliminate the NUL
in Str1.