r2 copy(Iter1 first, Iter1 last, Iter2 out);</pre>

<p>Obviously, there's no problem writing a generic version of
copy that works for all iterator types Iter1 and Iter2; however,
there are some circumstances when the copy operation can best be
performed by a call to <font size="2" face="Courier New">memcpy</font>.
In order to implement copy in terms of <font size="2"
face="Courier New">memcpy</font> all of the following conditions
need to be met:</p>

<ul>
    <li>Both of the iterator types Iter1 and Iter2 