Re: Pascal - C (2)

Ian Collins said:

Ruud wrote:
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?

No, C does not have nested functions, although some compilers support
them as extensions.

Right so far.


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.

Sorry, no.

Why not at least tell him about:

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

and

if(strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789", c) != NULL)

neither of which is a precise match, but each of which might be used in
similar situations.


One alternative is to use a regular expression library if
you have a lot of these.

That seems like overkill to me.


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.

Not in C.

Um, of course there is.

sprintf(Line1, "File size: %d byte%s", sSize, bytes == 1 ? "" : "s");

Note the extra flexibility that C gives you.


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?

Yes - sprintf can do this easily enough.

sprintf(Str1, "%s%c", Str2, Str3[5]);


Don't use C.

Um, he asked for a better way to do this in C. Not using C doesn't count.

C does not have string objects,

True, but it has a string format which works just fine.

of arrays of char and library functions to manipulate then.

I'm not sure what you mean here (unless "of" is a typo for "just" or "only"
or "merely", but yes, C has arrays of char and library functions to
manipulate them. Good!

If you are doing a lot of string manipulation, C might not be your best
choice. Scripting language like Perl are designed for string processing
and might be a better option.

ROTFL! If you are doing a shedload of string manipulation, C is a far
better choice than Perl. That is, if you want it to finish some time.

--
Richard Heathfield <http://www.cpax.org.uk>
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999
.

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