Is this code correct?
YouthBirthday birth; birth = new Birthday( "Terry", 23 );
Answer:
No. A reference variable for a child class (YouthBirthday) cannot be used for an object of a parent class (Birthday).
New Definition of YouthBirthday
Parents can accommodate children, but children can't accommodate parents. If you find this rule hard to remember, just think of yourself and your parents:
It is OK for you to go home and stay in your parent's house for a few days, but it's not OK for them to stay in your dorm room for a few days.
Now let us re-write YouthBirthday
in order to show more about polymorphism.
Say that you want two greeting() methods
for YouthBirthday:
- The parent's
greeting()method.- This will be included by inheritance.
- A method with the name of the sender as a parameter.
- This will be an additional method―it will not override the parent's method.
- In addition to what the parent's method does, this method will write out "How you have grown!! Love," followed by the name of the sender.
Here is a skeleton:
QUESTION 11:
Fill in the missing parts.