ShmoopTube
Where Monty Python meets your 10th grade teacher.
Search Thousands of Shmoop Videos
Computer Science Videos 112 videos
Just as you move your furniture into a new house before spending the night, you’ve got to spend a little time setting up your environment when yo...
Doubles and ints. At first glance, it may look like this video will be about baseball and football statistics. But they're actually computer scienc...
AP Computer Science: Classes and Objects Drill 1, Problem 1. Which of the following is a correct {/* Implementation */} for the isInsect method?
AP Computer Science 1.1 Inheritance, Abstraction, and Polymorphism 203 Views
Share It!
Description:
AP Computer Science 1.1 Inheritance, Abstraction, and Polymorphism. Which of the following are correct?
Transcript
- 00:00
Thank you We sneak and here's your smoke Do sure
- 00:05
try to sit up straight Just imagine you're a glam
- 00:08
metal bands hair Consider the following class hierarchy Upward arrows
- 00:12
indicate an inheritance relationship which of the following are correct
- 00:17
And here the potential answers Yeah All right as the
Full Transcript
- 00:22
problem states up arrows indicated inheritance relationship and we already
- 00:27
know that inheritance is just a big fancy word for
- 00:30
is a relationship No fast song is a song slow
- 00:34
song is a song too and we can go step
- 00:37
further and say power ballad is a slow song which
- 00:42
is a song Well we could extend this even further
- 00:44
by saying november rain is a power ballad november rain
- 00:48
than inherits any and all of the fields methods and
- 00:51
nested classes from power ballad which inherits from slow song
- 00:56
which inherits from song for exam song would contain members
- 01:00
that are relevant all songs and every subclass of song
- 01:03
things like are this name instruments song blank and so
- 01:07
on things that every song will have Well november rain
- 01:11
would be extremely specific like emotional axl rose vocal which
- 01:16
is something out every single half aside from simply knowing
- 01:19
their relationship between classes It's also important to know how
- 01:22
to properly declare and create a variable setting it all
- 01:27
up typically goes like this class variable named equals new
- 01:32
glass for supplies Yeah right left side of the equation
- 01:36
declares a variable to refer to An object song a
- 01:39
for example lets the compiler know that you're going to
- 01:42
use a to refer to data of the variety song
- 01:45
but that object doesn't actually yet exist On the other
- 01:49
side of the equation we get down and dirty and
- 01:51
actually a sign an object to that variable A new
- 01:54
power ballad for example would be created with song a
- 01:57
equals new power valid All right the question is asking
- 02:00
us which of these three option for declaring in creating
- 02:03
variables are correct starting with option one song a equals
- 02:07
new power balance and that's what we just did a
- 02:09
second ago and it works too and song be equals
- 02:12
New slow jam Yeah perfectly good way of creating a
- 02:15
slow jam Another good way would involve candles rose petals
- 02:19
and a saxophone solo But this is a little quicker
- 02:22
option One is good Option two is a little weird
- 02:25
It has as creating a slow song and power valid
- 02:28
and having them equal new song and slow song objects
- 02:32
but that's just not gonna fly the left side of
- 02:35
the equation declares variables name and its class and the
- 02:38
right side actually creates the object Option two is trying
- 02:42
to declare a variable of the type that's a subclass
- 02:44
of the actual object or creating that's like declaring that
- 02:48
you're going to be dracula for halloween But he actually
- 02:50
dress up some generic monster The option to option three
- 02:55
works like option one declaring variables and b to be
- 02:57
songs and then creates new fast song and slow song
- 03:01
objects So yeah three work with options One of three
- 03:04
working and to being wrong That makes the our answer
Related Videos
AP Computer Science 1.2 GridWorld Case Study and APIs. What is the direction of the actor?
AP Computer Science 1.4 Standard Algorithms. How many times will mystery be called for mystery(n) for n > 1?
AP Computer Science 2.3 Classes and Objects. Which of the following is correct implementation of the Country class?
AP Computer Science 3.4 Inheritance, Abstraction, and Polymorphism. Which of the following will satisfy the conditional if statement for boo, str,...
AP Computer Science 4.2 Standard Algorithms. What kind of algorithm is the following?