set<class> insert problem
<p>why is the following programm not working?
How can i fix it?</p>

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

using namespace std;

class K {

private:
    long a;
};

int main ()
{   
    K a;
    set&lt;K&gt; b;

    b.insert(a);

    return 0;
}
</code></pre>
