 and <tt>a</tt> intersect.
That is, it returns true if, there is a bit which is set in this
bitset, such that the corresponding bit in bitset <tt>a</tt> is
also set. Otherwise this function returns false.<br />
<b>Throws:</b> nothing.

<hr />
<pre>
size_type <a id = "find_first">find_first</a>() const;
</pre>

<b>Returns:</b> the lowest index <tt>i</tt> such as bit <tt>i</tt>
is set, or <tt>npos</tt> if <tt>*this</tt> has no on bits.

<hr />
<pre>
size_type <a id="find_next">find_next</a>(size_type pos) con