</div>
<p>Two-dimensional locators have additional requirements:</p>
<div class="highlight-cpp"><div class="highlight"><pre><span class="n">concept</span> <span class="n">RandomAccess2DLocatorConcept</span><span class="o">&lt;</span><span class="n">RandomAccessNDLocatorConcept</span> <span class="n">Loc</span><span class="o">&gt;</span>
<span class="p">{</span>
  <span class="n">where</span> <span class="n">num_dimensions</span><span class="o">==</span><span class="mi">2</span><span class="p">;</span>
  <sp