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| <div class="titlepage"><div><div><h2 class="title" style="clear: both"> |
| <a name="range.faq"></a><a class="link" href="faq.html" title="FAQ">FAQ</a> |
| </h2></div></div></div> |
| <p> |
| 1. <span class="emphasis"><em><span class="bold"><strong>Why is there no difference between <code class="computeroutput"><span class="identifier">range_iterator</span><span class="special"><</span><span class="identifier">C</span><span class="special">>::</span><span class="identifier">type</span></code> |
| and <code class="computeroutput"><span class="identifier">range_const_iterator</span><span class="special"><</span><span class="identifier">C</span><span class="special">>::</span><span class="identifier">type</span></code> |
| for <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special"><</span><span class="identifier">iterator</span><span class="special">,</span> <span class="identifier">iterator</span><span class="special">></span></code>?</strong></span></em></span> |
| </p> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| In general it is not possible nor desirable to find a corresponding <code class="computeroutput"><span class="identifier">const_iterator</span></code>. When it is possible to |
| come up with one, the client might choose to construct a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special"><</span><span class="identifier">const_iterator</span><span class="special">,</span><span class="identifier">const_iterator</span><span class="special">></span></code> object. |
| </p></blockquote></div> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| Note that an <a class="link" href="reference/utilities/iterator_range.html" title="Class iterator_range"><code class="computeroutput"><span class="identifier">iterator_range</span></code></a> is somewhat more |
| convenient than a <code class="computeroutput"><span class="identifier">pair</span></code> and |
| that a <a class="link" href="reference/utilities/sub_range.html" title="Class sub_range"><code class="computeroutput"><span class="identifier">sub_range</span></code></a> does propagate const-ness. |
| </p></blockquote></div> |
| <p> |
| 2. <span class="emphasis"><em><span class="bold"><strong>Why is there not supplied more types or |
| more functions?</strong></span></em></span> |
| </p> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| The library has been kept small because its current interface will serve |
| most purposes. If and when a genuine need arises for more functionality, |
| it can be implemented. |
| </p></blockquote></div> |
| <p> |
| 3. <span class="emphasis"><em><span class="bold"><strong>How should I implement generic algorithms |
| for ranges?</strong></span></em></span> |
| </p> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| One should always start with a generic algorithm that takes two iterators |
| (or more) as input. Then use Boost.Range to build handier versions on top |
| of the iterator based algorithm. Please notice that once the range version |
| of the algorithm is done, it makes sense not to expose the iterator version |
| in the public interface. |
| </p></blockquote></div> |
| <p> |
| 4. <span class="emphasis"><em><span class="bold"><strong>Why is there no Incrementable Range concept?</strong></span></em></span> |
| </p> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| Even though we speak of incrementable iterators, it would not make much sense |
| for ranges; for example, we cannot determine the size and emptiness of a |
| range since we cannot even compare its iterators. |
| </p></blockquote></div> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| Note also that incrementable iterators are derived from output iterators |
| and so there exist no output range. |
| </p></blockquote></div> |
| </div> |
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| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2003 -2010 Thorsten Ottosen, Neil Groves<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) |
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