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Re: Gets vertical skylines from grob stencils (issue 5626052)

From: address@hidden
Subject: Re: Gets vertical skylines from grob stencils (issue 5626052)
Date: Fri, 17 Feb 2012 08:42:40 +0100

On Feb 16, 2012, at 9:31 PM, Joe Neeman wrote:

On Thu, Feb 16, 2012 at 3:14 AM, address@hidden <address@hidden> wrote:

On Feb 16, 2012, at 11:40 AM, address@hidden wrote:

> The buildings are in increasing order, so this should work:
> Real last_end = -infinity_f;
> for (...)
>  {
>    if (i->y_intercept_ > -infinity_f)
>      return last_end;
>    last_end = i->end_;
>  }
> return infinity_f;


I know this is a lame question, but how would one write the reverse iterator.  I tried using reverse_iterator and g++ barfs, and I can't use the same syntax one would use in a for loop w/ a vector.

That's a bit hard to say without knowing what you tried... did you use rbegin() and rend()? 

Yup - I more or less copied the example from  As an experiment, try writing a reverse iterator in that file to the tune of:

  for (list<Building>::reverse_iterator i = buildings_.rbegin (); i != buildings_.rend (); ++i)

Anywhere in a function.  You should see a compiler error.

I fixed it, though, by reversing a copy of the list and iterating forward through it.


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