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

[Ian Collins]

Re: Pascal - C (2)

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.

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

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.

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?
>

Don't use C. C does not have string objects, of arrays of char and
library functions to manipulate then.

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.

--
Ian Collins

[jacob navia]

Re: Pascal - C (2)

Ian Collins wrote:

Ruud wrote:

>Hallo allemaal,
>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.

That is nonsense

sprintf(Line1," File size: %s bytes",sSize);

And you can save yourself transforming Size into a string with

sprintf(Line1," File size: %d bytes",Size);

>

>4) In Pascal I can "add" just one character of another string:
>>
> Str1 = Str2 + Str3[5];
>>
>Unfortunatel y 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?
>>

Don't use C. C does not have string objects, of arrays of char and
library functions to manipulate then.
>

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

The above can be done with

sprintf(str1,"% s%c",Str2,Str3[5]);

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.
>

C has problems with strings but it is usable. Other languages have other
(bigger) problems



--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique

http://www.cs.virginia.edu/~lcc-win32

[jacob navia]

Re: Pascal - C (2)

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?
>
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.
>

That one is simple enough

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.

Yes:
sprintf(Line1," File size: %s bytes",sSize);

And you can save yourself transforming Size into a string with

sprintf(Line1," File size: %d bytes",Size);

>
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.
The above can be done with

sprintf(str1,"% s%c",Str2,Str3[5]);

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

--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique

http://www.cs.virginia.edu/~lcc-win32

[Antoninus Twink]

Re: Pascal - C (2)

On 1 Nov 2008 at 22:23, jacob navia wrote:

Ian Collins wrote:

>Not in C.

>
That is nonsense
>
sprintf(Line1," File size: %s bytes",sSize);
>
And you can save yourself transforming Size into a string with
>
sprintf(Line1," File size: %d bytes",Size);

Yes. In fact, many implementations also provide an asprintf() function
in their standard library, which allocates memory for Line1 with malloc,
saving you the trouble of working out the size of the buffer needed and
eliminating possible overflows if you miscalculate.

[jacob navia]

Re: Pascal - C (2)

Antoninus Twink wrote:

On 1 Nov 2008 at 22:23, jacob navia wrote:

>Ian Collins wrote:

>>Not in C.

>That is nonsense
>>
>sprintf(Line1, "File size: %s bytes",sSize);
>>
>And you can save yourself transforming Size into a string with
>>
>sprintf(Line1, "File size: %d bytes",Size);

>
Yes. In fact, many implementations also provide an asprintf() function
in their standard library, which allocates memory for Line1 with malloc,
saving you the trouble of working out the size of the buffer needed and
eliminating possible overflows if you miscalculate.
>

Yes, that would be an even better alternative.

I answered so quickly because I was astonished that somebody could answer

"Not in C"

to such elemntary question!


--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique

http://www.cs.virginia.edu/~lcc-win32

[Ian Collins]

Re: Pascal - C (2)

jacob navia wrote:

Ian Collins wrote:

>>>

>Don't use C. C does not have string objects, of arrays of char and
>library functions to manipulate then.
>>

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

Why do you have to insult everyone?

>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.
>>

>
C has problems with strings but it is usable. Other languages have other
(bigger) problems
>

So what part of my statement do you disagree with? A pair of pliers has
problems but is usable for undoing bolts, would you use them if you had
a spanner that fitted?

Your C tunnel vision appears to have blinded you the the existence of
other languages.

--
Ian Collins

[jacob navia]

Re: Pascal - C (2)

Ian Collins wrote:

jacob navia wrote:

>Ian Collins wrote:

>>Don't use C. C does not have string objects, of arrays of char and
>>library functions to manipulate then.
>>>

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

Why do you have to insult everyone?
>

I am not insulting you. But failing to point
to sprintf as an obvious solution for that problem seems (to me)
a serious problem with the basics of the language.

I do not see why stating "you do not know enough C"
is an insult!

Besides I would have never said that if you wouldn't have
started with that arrogant

"Don't use C"

stuff.

>>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.
>>>

>C has problems with strings but it is usable. Other languages have other
>(bigger) problems
>>

So what part of my statement do you disagree with?

"Don't use C"



--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique

http://www.cs.virginia.edu/~lcc-win32

[Ian Collins]

Re: Pascal - C (2)

jacob navia wrote:

Ian Collins wrote:

>jacob navia wrote:

>>Ian Collins wrote:

>

>>>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.
>>>>
>>C has problems with strings but it is usable. Other languages have other
>>(bigger) problems
>>>

>So what part of my statement do you disagree with?

>
"Don't use C"
>

But why would you use C for string manipulation when there better
alternatives?

--
Ian Collins

[Nate Eldredge]

Re: Pascal - C (2)

Ruud <Ruud.Baltissen @apg.nlwrites:

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.

In this case, yes. There are macros in <ctype.hfor testing whether a
character is a member of various classes. This has the added advantage
of being more portable, in case you should find yourself using a
character set where 'A','B','C','D' ,'E','F' don't occur contiguously.
So a better way to write the above might be

#include <ctype.h>
/* ... */
if (isxdigit(c)) {
/* c is hexadecimal */
}

There are others, such as isalpha(), isdigit(), isspace(), isupper(),
etc. See your compiler's documentation or the C standard for a complete
list.

As a side note, some compilers (such as gcc) support an extension that
would let you do

switch (c) {
case 'A' ... 'F':
case '0' ... '9':
/* c is hexadecimal */
}

but that suffers the same character-set dependency as what you wrote
above, and is non-standard, and isn't really much simpler to read or write.

[jacob navia]

Re: Pascal - C (2)

Ian Collins wrote:

jacob navia wrote:

>Ian Collins wrote:

>>jacob navia wrote:
>>>Ian Collins wrote:
>>>>If you are doing a lot of string manipulation, C might not be your best
>>>>choice. Scripting language like Perl are designed for string
>>>>processin g
>>>>and might be a better option.
>>>>>
>>>C has problems with strings but it is usable. Other languages have other
>>>(bigger) problems
>>>>
>>So what part of my statement do you disagree with?

>"Don't use C"
>>

But why would you use C for string manipulation when there better
alternatives?
>

For many reasons:

1) C is a simple language easily available
2) Languages like perl/python have better string manipulation
primitives but have other problems like performance,
and availability.
3) If you use the pcre library (distributed with lcc-win) you have
all the power of perl in C without the problems associated
with perl.
4) Extensions to C like those proposed by lcc-win make the
problems with raw C strings disappear.

jacob


--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique

http://www.cs.virginia.edu/~lcc-win32

[S M Ryan]

Re: Pascal - C (2)

In article <ba5a4e47-f677-4e1c-b936-2621811c5534@f3 7g2000pri.googl egroups.com>,
Ruud <Ruud.Baltissen @apg.nlwrote:

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?

Not in standard C. Some compilers have an extension to allow this.

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.

if (isxdigit(c)) ...

There are various ways to represent sets as bit arrays in C. None are officially
sanctified as a set type.

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.

The standard C library <string.his not really intended to deal with
dynamickally resized strings. There are numerous libraries and implementation
that do all this for you. For example, Tcl has its Tcl_DString. Other solutions
are available.

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?

As above. You can layer on top of the standard library.

--
I'm not even supposed to be here today.

I ASSURE YOU WE'RE OPEN!

[Ian Collins]

Re: Pascal - C (2)

jacob navia wrote:

Ian Collins wrote:

>>>

>But why would you use C for string manipulation when there better
>alternatives ?
>>

>
For many reasons:
>
1) C is a simple language easily available
2) Languages like perl/python have better string manipulation
primitives but have other problems like performance,
and availability.

I'll concede performance, although scripting language string
manipulation is well optimised. Availability is debatable, requirements
for lots of string processing tend to be on platforms where other
languages are available.

3) If you use the pcre library (distributed with lcc-win) you have
all the power of perl in C without the problems associated
with perl.
4) Extensions to C like those proposed by lcc-win make the
problems with raw C strings disappear.
>

lcc-win is way less portable than most, if not all, scripting languages.

--
Ian Collins

[jacob navia]

Re: Pascal - C (2)

Ian Collins wrote:

jacob navia wrote:

>Ian Collins wrote:

>>But why would you use C for string manipulation when there better
>>alternative s?
>>>

>For many reasons:
>>
>1) C is a simple language easily available
>2) Languages like perl/python have better string manipulation
> primitives but have other problems like performance,
> and availability.

>
I'll concede performance, although scripting language string
manipulation is well optimised. Availability is debatable, requirements
for lots of string processing tend to be on platforms where other
languages are available.
>

Well the language choice is maybe not only for string manipulation.
Other reasons are probably more important, we do not know what
application the OP has. Note that he is translating from Pascal to
C. Pascal is even worst for string manipulation than C since
libraries like PCRE regular expressions are not easily available,
and regular expressions at all are not easy to find in Pascal.

C + the PCRE library is a very good choice for string manipulation,
combining performance and power.

>3) If you use the pcre library (distributed with lcc-win) you have
> all the power of perl in C without the problems associated
> with perl.
>4) Extensions to C like those proposed by lcc-win make the
> problems with raw C strings disappear.
>>

lcc-win is way less portable than most, if not all, scripting languages.
>

Maybe. But pcre is highly portable and can be used anywhere a
C compiler exists.


--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique

http://www.cs.virginia.edu/~lcc-win32

[Trent Josephsen]

Re: Pascal - C (2)

Ruud wrote:

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};

You can use strncat() to concatenate any number of characters from one
string to another. For this case you would use

strcpy(Str1, Str2);
strncat(Str1, &Str3[5], 1);

Observe that Str3[5] is a char, not a pointer to char, so you have to
take the address of it with & to pass it to strncat. This is the source
of the error you mentioned.