///////    File:  Calculator.C    ///////

// a simple calculator
#include    "Calculator.h"

void Calculator::on()
{     int ind;
      char op;
      double number;
      cf.show_number(eng.output());

      while ( (ind = cf.input(op, number))
                  != CalcFace::OFF )
      {  if ( ind != CalcFace::OPONLY )
              eng.operand( number );
         eng.operate( op );
	 number = ( op == 'c' || op == 'C' ) ? 0 : eng.output();
         cf.show_number(number);
      }
}