Trying to make a write function for a class and getting error
<p>I have implemented a write function for my class but iam getting error:</p>

<pre><code>class Fa{
private:
  string Q_;
  string F_;

public:
   void write(ostream&amp; out = cout) const{
   out&lt;&lt;Q_&lt;&lt;endl;
   out&lt;&lt;F_&lt;&lt;endl;
   }
};
</code></pre>

<blockquote>
  <p>Error:default argument given for parameter 1 of `void Fa::write(std::ostream&amp;) const' </p>
</blockquote>

<p>Can anybody please tell me what does this error mean and how could i avoid it?</p>
