title: Default move constructor in a sub class
body: <p>In C++11, if the base class has defined its own move (copy) constructor (assignment operator), does its subclass need to define its own move (copy) constructor (assignment operator) in where call the base class's corresponding constructor/operator is called explicitly?</p>
  
  <p>Is it a good idea to define the constructor, destructor, move/copy constructor (assignment operator) clearly every time?</p>
  
  <pre><code>struct Base {
      Base() {}
      Base(Base&amp;&amp; o);
  };
  
  struct Sub : public Base {
      Sub(Sub&amp;&amp; o) ;  // Need I do it explicitly ? If not,what the compiler will do for me
  };
  </code></pre>