AN>void reverse( char *s )
AN>{
AN>    if ( !s )
AN>        return;

AN>    char *e = s + strlen( s ) - 1;
AN>    while ( s < e )
AN>    {
AN>        *e ^= *s;
AN>        *s ^= *e;
AN>        *e-- ^= *s++;
AN>    }
AN>}
AN>