Java Reference
In-Depth Information
class, the definition of the method
DiscountSale
would not compile. If you omit
the definition of the method
bill
from the class
DiscountSale
, the output would
change to
floor mat Price and total cost = $10.0
floor mat Price = $11.0 Discount = 10.0%
Total cost = $11.0
Discounted item is not cheaper.
cup holder Price and total cost = $9.9
cup holder Price = $11.0 Discount = 10.0%
Total cost = $11.0
Items are not equal.
Note that all objects use the definition of
bill
given in the definition of
Sale
.
3. It would not be legal to add it to any class definition because the class
Sale
has no
method named
getDiscount
and so the invocation
theSale.getDiscount()
is not allowed. If the type of the parameter were changed from
Sale
to
DiscountSale
,
it would then be legal.
4 .
public boolean
equals(Object otherObject)
{
if
(otherObject ==
null
)
return false
;
else if
(getClass() != otherObject.getClass())
return false
;
else
{
DiscountSale otherDiscountSale =
(DiscountSale)otherObject;
return
(super.equals(otherDiscountSale)
&& discount == otherDiscountSale.discount);
}
}
5. The definition of
toString
always depends on the object and not on any type
cast. So, the definition used is the same as without the added type cast; that is, the
definition of
toString
that is used is the one given in
DiscountSale
.
6. It would not be legal to add it to any class definition because the parameter is
of type
Sale
, and
Sale
has no method named
getDiscount
. If the parameter
type were changed to
DiscountSale
, it would then be legal to add it to any class
definition.
7 .
ds was changed to map Price $ 5.0 discount 0.0%
Total cost $5.0
8 .
ds was not changed.
