. The first <tt>M</tt> bits are initialized to the
corresponding characters in <tt>s</tt>, where <tt>M =
min(s.size() - pos, n)</tt>. Note that the <i>highest</i>
character position in <tt>s</tt>, not the lowest, corresponds to
the least significant bit. That is, character position <tt>pos +
M - 1 - i</tt> corresponds to bit <tt>i</tt>. So, for example,
<tt>dynamic_bitset(string("1101"))</tt> is the same as
<tt>dynamic_bitset(13ul)</tt>.<br />
 <b>Throws:</b> an allocation error if memory is exhausted
(<tt>