How i am able to use string without #include<string>?
<p>It is given in the STL reference that string class is in string header,then without including the header how the following program is running without an error??</p>

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

using namespace std;

int main() {
  string s;
  cin&gt;&gt;s;
  cout&lt;&lt;"string entered is : "&lt;&lt;s;
}
</code></pre>

<p>I am using a g++ complier on ubuntu machine.</p>
