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AP Computer Science 1.2 Standard Data Structures 194 Views


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APCS: Standard Data Structures Drill 1, Problem 2. Which of the following methods are not appropriate for reuse in other programs?

Language:
English Language

Transcript

00:00

Thank you We sneak And here's your smoke du jour

00:05

brought to you by reusable methods A bit like wearing

00:08

the same shirt day after day Except fewer people will

00:11

notice All right which of the following methods are not

00:14

appropriate for reuse in other programs Hillary swap print array

00:20

carring in here is the code you skimming skimming skimming

00:23

that's giving Come on All right And here the potential

00:27

answers Causeway We thought yourself when your mother's competing you

00:31

and all right let's go Alright so looks like we're

00:34

being asked to figure out which method or methods would

00:37

not be suitable to reuse in another project somewhere else

00:41

The many coders frequently reuse when possible and what's the

00:44

point in reinventing the wheel if you've already written a

00:46

perfectly suitable piece of code for another project Well let's

00:49

start with phil array This one looks like it counts

00:53

the number of values in a given array whether it's

00:55

five imagers or five thousand and fills an empty array

00:58

with the values there's Nothing in this method that is

01:00

specific to this exact project So we could certainly reuse

01:03

this code elsewhere if necessary We can cross a d

01:06

off the list by how about swap Well it's not

01:10

just a clever name Looking at the code here it

01:13

appears swap takes two values in an array and well

01:16

stops them well More specifically it takes the first of

01:19

two array variables Moves it out of the way into

01:22

a variable called temp Ferreri then moves the second variable

01:27

this one into the first variables position in the array

01:30

We'll temp is then moved into the second variables place

01:33

into the switches Complete there's nothing and swap that tied

01:36

specifically to this project either So it's safe to say

01:39

that swap can work elsewhere and we can scratch Be

01:41

off the list All right What about print array for

01:44

the need of this is just one line How could

01:47

it not work somewhere else Well let's examine this four

01:51

loop more closely There are three expressions when you start

01:55

a four statement contained right there in the princess The

01:58

first is the initialization statement which runs once at the

02:01

beginning of the luke Here we set a variable up

02:04

to be our iterated er or counter it's eye with

02:07

a value of zero to start The second expression is

02:10

the terminator Which when It becomes false will terminate the

02:14

luke piri its eyes less than twenty meaning it'll continually

02:18

run until a value i becomes twenty or greater Meaning

02:21

it will run twenty times Cried it's in your base

02:24

number after the loop terminates The rest of the program

02:28

will continue running The third expression is the increment which

02:31

will run each time the loop runs It increases I

02:34

buy one each time so all this put together means

02:37

the variable i will started zero print a member of

02:40

the array then add one toe i over and over

02:42

and over until i reaches twenty Bottom line is this

02:46

method prince twenty values oven array then stops that might

02:49

work just fine for this program but can we really

02:51

use that code anywhere else What if we need to

02:54

print an array with only five values Or what about

02:57

honore With three hundred or an array that changes sizes

03:00

This print array method is just too inflexible to guarantee

03:02

that we could use it elsewhere That's not to say

03:04

it's bad code so we can't really rely on it

03:07

for any other purposes without modifications So the answer c

03:11

is the only one That fits the bill Three is

03:13

not suitable for dropping into another program and it really

03:17

is time to change that shirt Come on frankie Yeah

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