title: C++ vector of arrays
body: <p>Why does this work:</p>
  
  <pre><code>std::pair&lt;int, int&gt; p = {1,2};
  std::vector&lt;std::pair&lt;int, int&gt;&gt; vp = { {1,2}, {3,4} };
  </code></pre>
  
  <p>But this doesn't?</p>
  
  <pre><code>std::array&lt;int, 2&gt; a = {1,2}; // still ok
  std::vector&lt;std::array&lt;int, 2&gt;&gt; va = { {1,2}, {3,4} };
  </code></pre>
  
  <p>Using g++ 4.5.1 with <code>-std=c++0x</code>, the second line fails with:</p>
  
  <blockquote>
    <p>error: could not convert <code>‘{{1, 2}, {3, 4}}’</code> to <code>‘std::vector&lt;std::array&lt;int, 2u&gt; &gt;’</code></p>
  </blockquote>
  
  <p>Thanks</p>