ize(); ++i)
  (*this)[i] = (*this)[i] ^ rhs[i];
</pre>

<b>Returns:</b> <tt>*this</tt>.<br />
 <b>Throws:</b> nothing.

<hr />
<pre>
dynamic_bitset&amp; <a id=
"op-sub-assign">operator-=</a>(const dynamic_bitset&amp; rhs)
</pre>

<b>Requires:</b> <tt>this-&gt;size() == rhs.size()</tt>.<br />
 <b>Effects:</b> Computes the set difference of this bitset and
the <tt>rhs</tt> bitset. This is equivalent to:

<pre>
for (size_type i = 0; i != this-&gt;size(); ++i)
  (*this)[i] = (*this)[i] &amp;&amp; !rhs[i];
</pre