C++ -- which constructor of string is call when we use string(0)?
<p>Given the following code,</p>

<pre><code>class A
{
public:
  A() : str(0) {}
private:
  string str;
};
</code></pre>

<p>Based on this <a href="http://www.cplusplus.com/reference/string/string/string/" rel="nofollow">http://www.cplusplus.com/reference/string/string/string/</a></p>

<pre><code>string ( );
string ( const string&amp; str );
string ( const string&amp; str, size_t pos, size_t n = npos );
string ( const char * s, size_t n );
string ( const char * s );
string ( size_t n, char c );
template&lt;class InputIterator&gt; string (InputIterator begin, InputIterator end);
</code></pre>

<p>I don't see which constructor of string is called when we use the 'str(0)'.</p>

<p>Question> Can someone tell me which string constructor is used for 'str(0)'?</p>
