title: C++ Circular Inheritance and Class
body: <p>I'm getting the error "circular inheritance problem encountered in 'atan'" on the last line. I'm confused since it only occurs in that line and not in main(). I only include  in the cpp file and not anywhere else. Since the error is only in the class function I guess I'm doing something wrong with the class, but can't figure out what it is.</p>
  
  <p>*I only threw in the main as an example of when it works. Doesn't actually serve a purpose.</p>
  
  <p>//.h file</p>
  
  <pre><code>#ifndef CIRCLE_H_
  #define CIRCLE_H_
  
  
      class Circle {
      public:
          Circle(int minVertex=12);
          ~Circle();
      private:
          int pixels;
      };
  
  #endif /* CIRCLE_H_ */
  </code></pre>
  
  <p>// cpp file</p>
  
  <pre><code>#include &lt;circles.h&gt;
  #include &lt;cmath&gt;
  using namespace std;
  
  int main(){
      double pi = abs(9);
  }
  
  
  Circle::Circle(int minVertex = 12) {
      pixels = 1150;
      double pi = atan(0) *2; // problem here
  }
  </code></pre>