Convert Class Object to String
<p>I have an assignment for a class that requires me to convert a class object, <code>clock_time</code>, to a string using two required, instructor-defined empty functions: <code>to_string()</code>  and an overloaded &lt;&lt; operator. I am not able to get it to work and I am unsure why.</p>

<pre><code>clock_time::clock_time(int h, int m, int s)
{
    set_time(h, m, s);
}

void clock_time::set_time(int h, int m, int s)
{
    _seconds = h * 3600 + m * 60 + s;
}

string to_string(clock_time c)
{
    ostringstream ss;
    ss &lt;&lt; c;
    return ss.str();
}

ostream&amp; operator&lt;&lt;(ostream &amp;out, clock_time c)
{
    out &lt;&lt; to_string(c);
    return out;
}
</code></pre>