Re: Opinion poll: for loop vs while loop with Iterators.

Lew <>
Thu, 21 Dec 2006 22:39:06 -0500
Daniel Pitts wrote:

My opinion on the for statement:
It is useful when there are 2 simple statements (initializer and
post-loop), one conditional expression, and 1 more statement (compound
or otherwise)

That use case lies far over toward the "for" end of the seesaw.

The iterator concept does NOT fall into that category, unless you write
it like this:
E e;
for (Iterator<E> i = getIterator(); i.hasNext(); doSomething(e)) {
    e =;

Which IMHO is ugly.

That use case lives nearer the middle.

I happen to like that idiom, except that I declare "E e" inside the loop and
put the doSomething() there, too, but I understand perfectly well why it seems

I rarely will put a workhorse expression inside the for () setup; they belong
in the body.

My version would be (assuming a collection as the progenitor of the iterator):

for ( Iterator<E> iter = collection.getIterator(); iter.hasNext(); )
   E entry =;
   doSomething( entry ); // or just doSomething( )

In most cases, that becomes

for( E entry : collection )
   doSomething( entry );

anyway, and the ugliness vanishes very far.

Lew wrote:

I much prefer the for loop, except when there is no loop variable.

I lied. I use for() {}, while () {} and do {} while ();.

I prefer all three. I like "for ( ;; )" to set up unbounded loops.

- Lew

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