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Re: what is the difference between these statement

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Ben Bacarisse <ben.usenet@bsb.me.uk> writes:

> Dr Nick <3-nospam@temporary-address.org.uk> writes:
>
>> Ben Bacarisse <ben.usenet@bsb.me.uk> writes:
>>
>>> Dr Nick <3-nospam@temporary-address.org.uk> writes:
>>> <snip>
>>>> There is a useful function (in ctypes.h) for this - called "isspace".
>>>> So you can replace your pieces of code with:
>>>> #include <ctypes.h>
>>>> ...
>>>> if(isspace((unsigned char)c) {then go to next character }
>>>> else ( increase no of word}
>>>
>>> I don't think K&R have introduced these by the time this exercise is
>>> set.  No reason not to mention them, of course, but you then have to
>>> explain the (unsigned char)c cast:
>>
>> At this time I didn't know it was from K&R.
>
> No indeed.  And as I said, there's no reason not to mention them.
>
>>> <snip>
>>>> The "(unsigned char)" bits are in for technical reasons; they prevent
>>>> the isspace function doing something silly if you pass an unusual value
>>>> to them (like and end of file, or perhaps certain accented characters
>>>> depending on various other things).
>>>
>>> The OP has now posted their full code and they correctly have
>>>
>>>   int c;
>>>   ...
>>>   ... c = getchar() ...
>>>
>>> so the cast is not needed.  In fact, if they changed the code so that
>>> EOF might to be passed to a ctype function, the cast makes the code
>>> wrong!  I realise you could not know that c was an int set by getchar()
>>> at the time you posted, but there was always a risk such advice could be
>>> wrong or confusing.
>>>
>>> <snip>
>>
>> OK. I'll go away now.  Sorry for trying to be helpful but not being
>> telepathic.
>
> I'm sorry if I offended you.  Please continue to give advice.  The more
> voices here the better, in my opinion.

Thanks.  Sorry if I was touchy.

To try to turn this into something constructive.  Are there any
circumstances in which casting the argument to a ctype function to
unsigned char would cause problems (apart from doing it before checking
for EOF - like "toupper(getchar())").

I can't think of one.
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what is the difference between these statement ashu <ashishmourya21@gmail.com> - 2012-05-06 04:11 -0700
  Re: what is the difference between these statement Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-05-06 12:29 +0100
    Re: what is the difference between these statement ashu <ashishmourya21@gmail.com> - 2012-05-06 07:56 -0700
    Re: what is the difference between these statement ashu <ashishmourya21@gmail.com> - 2012-05-06 08:01 -0700
      Re: what is the difference between these statement Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-05-06 18:54 +0100
  Re: what is the difference between these statement Dr Nick <3-nospam@temporary-address.org.uk> - 2012-05-06 15:39 +0100
    Re: what is the difference between these statement Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-05-06 18:32 +0100
      Re: what is the difference between these statement Dr Nick <3-nospam@temporary-address.org.uk> - 2012-05-06 19:23 +0100
        Re: what is the difference between these statement Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-05-06 22:52 +0100
          Re: what is the difference between these statement Dr Nick <3-nospam@temporary-address.org.uk> - 2012-05-07 08:08 +0100
            Re: what is the difference between these statement Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-05-07 12:44 +0100
              Re: what is the difference between these statement Dr Nick <3-nospam@temporary-address.org.uk> - 2012-05-09 06:54 +0100
                Re: what is the difference between these statement James Kuyper <jameskuyper@verizon.net> - 2012-05-09 07:46 -0400
                Re: what is the difference between these statement Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-05-09 15:32 +0100
                Re: what is the difference between these statement Tim Rentsch <txr@alumni.caltech.edu> - 2012-05-09 12:02 -0700
                Re: what is the difference between these statement jgk@panix.com (Joe keane) - 2012-05-10 17:46 +0000
                Re: what is the difference between these statement Keith Thompson <kst-u@mib.org> - 2012-05-10 11:47 -0700
                Re: what is the difference between these statement Tim Rentsch <txr@alumni.caltech.edu> - 2012-05-11 08:55 -0700
                Re: what is the difference between these statement jgk@panix.com (Joe keane) - 2012-05-13 20:09 +0000
                Re: what is the difference between these statement Kaz Kylheku <kaz@kylheku.com> - 2012-05-13 23:24 +0000
                Re: what is the difference between these statement Tim Rentsch <txr@alumni.caltech.edu> - 2012-05-14 11:46 -0700

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