title: sizeof(value) vs sizeof(type)?
body: <p>Considering :</p>
  
  <pre><code>double data; 
  double array[10]; 
  std::vector&lt;int&gt; vec(4, 100); 
  MyClass myclass;   
  </code></pre>
  
  <p>Is there a difference between :</p>
  
  <pre><code>sizeof(double);
  sizeof(double[10]);
  sizeof(std::vector&lt;int&gt;);
  sizeof(MyClass);
  </code></pre>
  
  <p>and </p>
  
  <pre><code>sizeof(data);
  sizeof(array);
  sizeof(vec);
  sizeof(myclass);
  </code></pre>
  
  <p>Are the two syntaxes different or strictly equivalent ? Are all of them evaluated at compile-time ? If not, which one is evaluated at run-time ?</p>