AP Computer Science 2.4 Classes and Objects

Which of the following is not a legal method Call

shmoop yeah but near the potential Answer a lot of

roman numerals and remember roman soldier of walk into a

bar with girlfriend orders five years Okay sounds like we're

being asked which of the given method calls art in

fallon But what on earth are method calls and when

will you ever use it Well typically large java project

will be split up into separate classes classes to make

code more manageable We might have one class handling saving

and loading a file another class handling networking class handling

graphics and so on That way when there's a bug

in a certain function or the code needs to be

modified all the relevant code is in one place The

main class will then call various methods from other classes

is needed right Well small programming projects may not need

so many separate classes but as things get more complicated

while it helps a great deal the thing about how

small company might be if just one or two people

handled everything in a garage Well that's perfectly manageable because

the relatively small operation with a little work to do

but a large company of dozens or hundreds of people

would have to be split into departments each with different

tasks like think about how hard it is for amazon

the ship product right And when it's time to do

something with the same marketing you'd have to give him

a call Yes hello marketing department We need to get

our name out there and i'm thinking pigeon sweaters will

put thousands of tiny sweaters on pigeons all over the

city with our branding all over them they'll be everywhere

can fail right We're calling elsewhere to make a request

is the same thing we're doing with method calls Yes

with fewer pigeon sweat and now let's look at our

options and figure out which are invalid Option one tries

to call a method with object see but see is

just a null object and hasn't been specified as a

new anything so option one won't work at all Option

two tries to call the shed leaves method with object

b which looks like it's gonna work Object is in

oak object and the shed leaves method resides within the

class Looking good Option to option three tries to call

the shed leaves method with object a but a is

a pine object The pine class doesn't contain a shed

leaves method It's only got shed needles Option three is

not going to cut it That makes our answer D

because options one of three are invalid and so our 00:02:55.383 --> [endTime] pigeon sweaters