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Subject: Re: Problem trying to implement generics.
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From: Ray Blaak <blaak@infomatch.com>
Message-ID: <uoftu406j.fsf@infomatch.com>
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Date: 18 Apr 2001 09:55:48 -0700
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Date: 2001-04-18T09:55:48-07:00
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"Ayende Rahien" <Dont@spam.me> writes:
> "Tucker Taft" <stt@averstar.com> wrote in message
> > Interestingly enough, the standard Iterator in Java
> > uses:
> >      while (Iter.hasNext()) {
> >          X = Iter.next();
> >          ...
> >      }
> Why [not] use it like this?
> for (;Iter.hasNext(); X = Iter.next() ){
>     //do stuff
> }
> 
> Is much more readable, IMO.

Because that is wrong :-).

With the above for loop, the nth iteration has the value for iteration
n-1. The first iteration has no value at all. I.e. it is equivalent to:

  while(Iter.hasNext())
  { // ...do stuff with X...
    X = Iter.next();    
  }

The .next() method returns the current value and sets the iterator to be at
the next one. It does not return the next value per se.

A correct for loop is:

  for(; Iter.hasNext(); )
  { X = Iter.next();
    // ...do stuff with X...
  }

but that is redundant, so a while loop is better.

-- 
Cheers,                                        The Rhythm is around me,
                                               The Rhythm has control.
Ray Blaak                                      The Rhythm is inside me,
blaak@infomatch.com                            The Rhythm has my soul.