title: Virtual method, but non-virtual destructor
body: <pre><code>class A {
  public:
      virtual void x() = 0;
      virtual void y() = 0;
      virtual int z() = 0;
  };
  
  class B: public A {
  public:
      void x();
      void y();
      int z();
      void w();
  };
  
  class C: public A {
  public:
      void x();
      void y();
      int z();
  };
  </code></pre>
  
  <p>"<em>Class 'i' has virtual method 'j' but non-virtual destructor</em>", where i = A, B C, and j = x, y, z</p>
  
  <p>Do I need a virtual destructor?</p>