ut not both). An operator may be overloaded if at least one
          of its parameters is a user-defined type. In this case, the
          <tt>real_p</tt> is the 2nd argument to <tt>operator<span class=
          "operators">&gt;&gt;</span></tt>, and so the proper overload of
          <tt class="operators">&gt;&gt;</tt> is used, converting
              <tt class="quotes">','</tt> into a character literal parser.<br>
          <br>
           The problem with omitting the <tt>ch_p</tt> call should be obvi