Override standard function which is friend of class
<p>There is such class:</p>

<pre><code>#include &lt;iostream&gt;
#include &lt;cmath&gt;

class Element {
private:
  int val;
public:
  Element(int val_){ val = val_;}
  friend Element std::pow(Element a, int exp);
};
</code></pre>

<p>I'd like to override standard function pow, which is friend of class Element, to work with objects of my class. However, there is following error during compilation:</p>

<pre><code>error: ‘Element std::pow(Element, int)’ should have been declared inside ‘std’
</code></pre>

<p>How to override standard pow function?</p>
