title: c++ a missing vtable error
body: <p>I am getting a really weird error related to missing vtable for a given class constructor and destructor. Please help me to resolve this.</p>
  
  <p>Undefined symbols for architecture i386:</p>
  
  <pre><code>  "vtable for A", referenced from:
        A::A() in A.o
        A::~MissionController() in A.o
    NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
  ld: symbol(s) not found for architecture i386
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  </code></pre>
  
  <p>Code snippet;</p>
  
  <h1>.h file:</h1>
  
  <pre><code>class A: public B
  
    public:
       A();
      ~A();
  
  };
  </code></pre>
  
  <h1>.cpp file..</h1>
  
  <pre><code> A::A()   
  {
  
  
  }
  
  A::~A()
  {
  
  
  }
  </code></pre>