ShmoopTube

00:01

Sorry And here's your shmoop du jour brought to you

00:05

by boolean Very bills It's True A newbie classes to

00:12

be written that includes the following data members string species

00:16

into hive number boolean is queen and into a number

00:21

of bees assumed that had given b cannot change residences

00:25

or upgrade to queen stats which of the following should

00:28

be declared as a static variable I've number number of

00:32

bees is queen all right What the potential answers Here

00:35

we go we're on the numeral time and okay we're

00:40

being asked which variable or variable should be that flared

00:43

static before we can answer this let's examine what static

00:46

variables are what they do and why they're important Well

00:49

a static variables one whose value will remain constant across

00:52

an entire class of objects If we change the variables

00:55

value for one of the objects it'll reflect across every

00:58

object of that class Well to visualize this let's imagine

01:01

you have a workshop where you build coffee tables and

01:03

you're writing a program to keep track of the tables

01:05

you've made you might have a class called coffee table

01:08

and assign it Some data members such as material type

01:11

table length and numb legs will make numb legs a

01:14

static variables for each table that gets created will need

01:16

to declare the material type length and number of legs

01:19

thiss once made a pine fifty inches long and has

01:22

four legs solid This one's cherry wood very fancy thirty

01:25

inches long and has four legs and this one is

01:28

a metal table thirty inches long and with four legs

01:31

Wait you know what That first one isn't pine it's

01:34

oak We need to go back and change it There

01:37

we go in this example the material type variable is

01:40

not static so when we change that variable for one

01:42

object it doesn't affect the others of that class Numb

01:46

legs however has been declared a static If we change

01:49

that variable for any coffee table object it affects all

01:53

of them on your snacks are all over the floor

01:56

In the case of the bees we've got three variables

01:58

and move to the side which would be more was

01:59

appropriately status we'll hide number is a variable we're using

02:03

to identify which hive each particular be belongs to If

02:06

this were static every bee would belong to the same

02:08

single hive that wouldn't work is a static variable Things

02:12

would get too crowded really quickly Yeah is clean also

02:16

wouldn't work for a couple of reasons First the question

02:18

specified that abi's clean status could not be changed so

02:21

that's a deal breaker but just as importantly even if

02:24

we could change it having that variable static would mean

02:26

everyone would either be a queen or no one would

02:28

be anything at all and that's not gonna work for

02:31

us either So now we're left to look at number

02:33

of bees which is intended to be a counter keeping

02:35

track of exactly that If number of these were static

02:39

and we update this variable for one be it affects

02:42

all of them So that's pretty useful of our possible

02:45

answer b is the only one that fits the bill

02:47

we've identified the on ly number of b should be

02:49

static before we go it's important to remember the distinction

02:52

between static variables and final variables here the sound similar

02:56

but as we learned a static variable is one that

02:59

remains the same across every object in a class If

03:02

it changes for one object it changes for every object

03:05

in that class where's final variables which were not used

03:08

in this question are to find once and never change

03:11

their values you can consider final variables to be set

03:15

in stone like you're no political uncle on facebook Yeah 00:03:19.92 --> [endTime] okay

Full Transcript