function system() from stdlib.h

[Richard Bos]

Re: function system() from stdlib.h

CBFalconer <cbfalconer@yah oo.comwrote:

Chris Dollin wrote:

santosh wrote:

Is there a specific reason for doing while( ... ) {} instead of
while( ... ); other than readability? I consider the latter form
to be more readable, but I may be in the minority regarding that.

Readability. I find `;` to be more missable (and more likely to
be an accident) than {}. One's parsecage may vary.

>
Try:
>
while (side_effects) continue;

That's a good one; another I like is putting the semi-colon on a line of
its own. That's unusual enough to be clear. Like this:

while (side_effects--)
;

Richard

[Chris Dollin]

Re: function system() from stdlib.h

CBFalconer wrote:

Chris Dollin wrote:

>santosh wrote:
>>

... snip ...

>>>
>>Is there a specific reason for doing while( ... ) {} instead of
>>while( ... ); other than readability? I consider the latter form
>>to be more readable, but I may be in the minority regarding that.

>>
>Readability. I find `;` to be more missable (and more likely to
>be an accident) than {}. One's parsecage may vary.

>
Try:
>
while (side_effects) continue;

I shan't /try/ it; while I can see that some would find it OK,
it looks like an abomination to me. Of course what I'd /prefer/
is `endwhile` [1] ... but C Is Not Built That Way And I Can't
Change It.

[1] Or `endrepeat`, as in `repeat A while B do C endrepeat`.

--
Chris "electric hedgehog" Dollin
"- born in the lab under strict supervision -", - Magenta, /Genetesis/

[Keith Thompson]

Re: function system() from stdlib.h

Chris Dollin <chris.dollin@h p.comwrites:

CBFalconer wrote:

[...]

>Try:
>>
> while (side_effects) continue;

>
I shan't /try/ it; while I can see that some would find it OK,
it looks like an abomination to me. Of course what I'd /prefer/
is `endwhile` [1] ... but C Is Not Built That Way And I Can't
Change It.

Of course you can change it:

#define endwhile }
#define endif }
....

(But don't expect anyone to read your code if you commit such an
abomination.)

--
Keith Thompson (The_Other_Keit h) kst-u@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Richard Bos]

Re: function system() from stdlib.h

Chris Dollin <chris.dollin@h p.comwrote:

CBFalconer wrote:
>

Chris Dollin wrote:

Readability. I find `;` to be more missable (and more likely to
be an accident) than {}. One's parsecage may vary.

Try:

while (side_effects) continue;

>
I shan't /try/ it; while I can see that some would find it OK,
it looks like an abomination to me. Of course what I'd /prefer/
is `endwhile` [1] ... but C Is Not Built That Way And I Can't
Change It.
>
[1] Or `endrepeat`, as in `repeat A while B do C endrepeat`.

If you want to hack on the Bourne shell source, you know where to find
it. Yuck.

Richard

[Default User]

Re: function system() from stdlib.h

Richard Bos wrote:

CBFalconer <cbfalconer@yah oo.comwrote:
>

Chris Dollin wrote:

santosh wrote:
>
>Is there a specific reason for doing while( ... ) {} instead of
>while( ... ); other than readability? I consider the latter form
>to be more readable, but I may be in the minority regarding that.
>
Readability. I find `;` to be more missable (and more likely to
be an accident) than {}. One's parsecage may vary.

Try:

while (side_effects) continue;

>
That's a good one; another I like is putting the semi-colon on a line
of its own. That's unusual enough to be clear. Like this:
>
while (side_effects--)
;

The first C coding standard I worked under mandated/suggested that. It
works pretty well, although these days I tend to use empty braces:

while (side_effects--)
{
}



Brian

[Simon Biber]

Re: function system() from stdlib.h

Christopher Layne wrote:

britzkrieg wrote:
>

>Hi,
>>
>I had write a program for Windows OS and put the following line:
>>
>system("pause" )
>>
>that use the "pause" command from DOS to pause the screen until I push
>a button. How to get the same result in Linux's bash ?
>>
>thanks a lot

>
"read"
>
Literally:
>
#!/bin/bash
read -p "press enter key when ready"
<whatever else>
>
Now if it's a modern version of bash and you're commited to being bash
specific:
>
read -s -n 1 -p "press any key when ready"
>
Silent echo, 1 char max

If you want to exactly duplicate MS-DOS's pause command:

system("read -s -n 1 -p \"Press any key to continue . . . \"; echo;");

The extra echo command is necessary as pause adds a newline after you
press a key.

--
Simon.

[Chris Dollin]

Re: function system() from stdlib.h

Richard Bos wrote:

Chris Dollin <chris.dollin@h p.comwrote:
>

>CBFalconer wrote:
>>

Chris Dollin wrote:

>

>Readability. I find `;` to be more missable (and more likely to
>be an accident) than {}. One's parsecage may vary.
>
Try:
>
while (side_effects) continue;

>>
>I shan't /try/ it; while I can see that some would find it OK,
>it looks like an abomination to me. Of course what I'd /prefer/
>is `endwhile` [1] ... but C Is Not Built That Way And I Can't
>Change It.
>>
>[1] Or `endrepeat`, as in `repeat A while B do C endrepeat`.

>
If you want to hack on the Bourne shell source, you know where to find
it. Yuck.

I don't. Why would you think I did?

(Yes, I /know/ that the Bourne shell was writting with algolifying
macros. C isn't built that way, and I can't change it, and I
have no interest in trying to fake a better-according-to-me
syntax using macros, for all the reasons behind your and
Keith's expressions of distaste. To get a more pleasing grammar
I go to -- or implement -- other languages.)

--
Chris "electric hedgehog" Dollin
There' no hortage of vowel on Uenet.

[Richard Bos]

Re: function system() from stdlib.h

Chris Dollin <chris.dollin@h p.comwrote:

Richard Bos wrote:
>

Chris Dollin <chris.dollin@h p.comwrote:

CBFalconer wrote:
>
Try:

while (side_effects) continue;
>
I shan't /try/ it; while I can see that some would find it OK,
it looks like an abomination to me. Of course what I'd /prefer/
is `endwhile` [1] ... but C Is Not Built That Way And I Can't
Change It.
>
[1] Or `endrepeat`, as in `repeat A while B do C endrepeat`.

If you want to hack on the Bourne shell source, you know where to find
it. Yuck.

>
I don't. Why would you think I did?

If you want the origin for a standard hacker idiom, you know where to
find it.

(Yes, I /know/ that the Bourne shell was writting with algolifying
macros. C isn't built that way, and I can't change it, and I
have no interest in trying to fake a better-according-to-me
syntax using macros, for all the reasons behind your and
Keith's expressions of distaste.

No, you don't, because at least one of the reasons behind my distaste is
that I find the endrepeat grammar _not_ better, but overly voluble and
frequently less legible.

Richard

[Chris Dollin]

Re: function system() from stdlib.h

Richard Bos wrote:

Chris Dollin <chris.dollin@h p.comwrote:
>

>Richard Bos wrote:
>>

Chris Dollin <chris.dollin@h p.comwrote:
>
>CBFalconer wrote:
>>
Try:
>
while (side_effects) continue;
>>
>I shan't /try/ it; while I can see that some would find it OK,
>it looks like an abomination to me. Of course what I'd /prefer/
>is `endwhile` [1] ... but C Is Not Built That Way And I Can't
>Change It.
>>
>[1] Or `endrepeat`, as in `repeat A while B do C endrepeat`.
>
If you want to hack on the Bourne shell source, you know where to find
it. Yuck.

>>
>I don't. Why would you think I did?

>
If you want the origin for a standard hacker idiom, you know where to
find it.

That's not an answer.

>(Yes, I /know/ that the Bourne shell was writting with algolifying
> macros. C isn't built that way, and I can't change it, and I
> have no interest in trying to fake a better-according-to-me
> syntax using macros, for all the reasons behind your and
> Keith's expressions of distaste.

>
No, you don't, because at least one of the reasons behind my distaste is
that I find the endrepeat grammar _not_ better, but overly voluble and
frequently less legible.

Ah. Well, it would have helped if you'd said that. Usually when
I've seem people yuck over the Bourne shell its the algolification-
via-macros that's the issue, not the intended syntax. (I'm curious
whether you've seen a language with the repeat-endrepeat syntax,
since the one I know it from is Pop11.)

Grammatical tastes differ.

Um, this is barely topical: if you're bothered to respond, I'll
take email.

--
Chris "electric hedgehog" Dollin
"He's dead, Jim, but not as we know it." Unsaid /Trek/.