span><span class=identifier>last</span><span class=special>; </span><span class=special>}

        </span><span class=keyword>template </span><span class=special>&lt;</span><span class=keyword>typename </span><span class=identifier>T</span><span class=special>&gt;
        </span><span class=identifier>T </span><span class=identifier>filter</span><span class=special>(</span><span class=identifier>T </span><span class=identifier>ch</span><span class=special>) </span><span class=keyword>const
        </span><s