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Description:
AP Computer Science 4.2 Standard Data Structures. Which implementation will find "k" within the String array alphabet and turn it into "funk"?
Transcript
- 00:03
Here's your extra funky shmoop du jour the kind of funky
- 00:08
not food that's gone bad punky [Rat smelling wedge of cheese]
- 00:16
what's the fun in funk which implementation will find K within the
- 00:21
string array alphabet and turn it into funk and hear your potential answers
- 00:30
.....here we go alright time to get our hands dirty well [Boy digging up mud]
Full Transcript
- 00:32
we've got a big ol array where each element is a letter of the alphabet and
- 00:36
we have to dig through it until we find the letter K and turn it into some card [Boy digging up alphabet blocks]
- 00:41
option one starts with a for loop but where typical loop starts with its
- 00:45
iterator at zero and works upwards this one starts with the iterator at some
- 00:49
value alphabet dot length minus one well assuming our alphabet array is 26
- 00:55
elements long that will make I equal to 25 the loop will terminate when I stops
- 00:59
being greater than or equal to zero and subtract one from I each time the loop
- 01:03
cycles well the if statement inside the loop will then check the alphabet array [Finger points to if statement]
- 01:07
at index I see if it equals the letter K most of the time it won't so the code
- 01:12
within the if statement won't get executed but on a slight chance that we [Doctor speaking with patient]
- 01:16
get a positive we create the string fresh and give it a value fun then
- 01:22
change the value of that K we found to be fun plus K funky clever and on looks
- 01:27
like option one will work all right let's try option two creates a slightly [Option 2 loop appears]
- 01:31
more typical loop starting its iterator at zero and working upward until it's no
- 01:34
longer less than the alphabet arrays length well each time the loop cycles [Loop riding a bicycle]
- 01:38
the if statement checks to see if we're working with a K NSO gives us the
- 01:42
strings fresh with the value funky and then uses a substring operation a slice
- 01:48
off the first K and the KY and replace our K with funk so option two should
- 01:54
work to some string operations are a lot like slicing that gross little nub off [Person slices end of banana]
- 01:59
the end of a bananas you know all right so so you've got the springs
- 02:03
banana and you want to get rid of the B at the beginning in the final a well you
- 02:07
could substring it with the indices of one and five to swing the knife there [Knife cuts away letters b and a]
- 02:11
and create a new string well that's exactly what's happening here with funky
- 02:15
being mutilated to create fun in so many senses of the phrase option three takes
- 02:20
it another direction using a while loop well here we've been given the iterator
- 02:26
I with a value of one and while the alphabet element at index I minus 1 is
- 02:31
not K it adds one to the I and loops again so this will go on over and over
- 02:37
and over until we get a K which points a while loop will break and we'll finally
- 02:41
get to move down to changing that array value at index I to funk so a job well
- 02:45
done let's just print our array to the console and we can admire our handiwork [array printing]
- 02:50
so oh oh no we didn't change K we changed L instead we must have
- 02:56
overlooked something and there it is right there in our while loop we're [Man points to while loop]
- 02:59
checking to see if the string at index I minus 1 is K and when it is we alter a
- 03:05
different array position entirely I so know option 3 does not work is given
- 03:11
could we tweak it and fix it sure it would be easy but as the stands now all [Woman tweaking a loop function frame]
- 03:15
the options 1 & 2 don't fake the funk
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