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AP Computer Science 1.2 Standard Data Structures 194 Views
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Description:
APCS: Standard Data Structures Drill 1, Problem 2. Which of the following methods are not appropriate for reuse in other programs?
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
Full Transcript
- 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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