polymorphic functions

• The two different prototypes for ViewAcct imply there will be two different function definitions.

  • Brass::ViewAcct( )
  • BrassPlus::ViewAcct( )

• The driver will use the object type to choose.

  • Brass blue(...);
  • BrassPlus yellow(...);
  • blue.ViewAcct( ); // use Brass::ViewAcct( )
  • yellow.ViewAcct( ); // use BrassPlus::ViewAcct( )

• similarly for Withdraw( );