title: Initializing sizes of nested vectors
body: <p>If I wanted to create a vector of vectors of the same size, how can I do this with one initialization line?</p>
  
  <p>e.g.</p>
  
  <p><code>std::vector&lt;std::vector&lt;int&gt;&gt; vv(5)</code> would default initialize 5 vectors, but how to initialize those 5 vectors to a size?</p>