AP Computer Science 1.1 Review of the Basics

Pretty simple Request We just have to prove to the

test and to ourselves that we know how to read

java code and figure out what it does Well it's

Not merely a pest problem This kind of thing is

done all the time when debugging program right but also

comes up quite a bit when software engineers have to

maintain or update pulled code Occasionally you'll have to work

with stuff that had been written five or ten years

ago or more perhaps by someone who is no longer

on the project and maybe they didn't leave comments in

the code so it's tough to figure out exactly what

it was meant to do or they thought they were

being really cute and they left their comments and cling

on Well good luck with that Anyway in this case

is just eight lines but we can already see that

there are a couple of loops that end up doing

an awful lot in that short space So let's go

through and decode this baby step by step All right

up top line one sets us up with manager i

with a value of five Go ahead and write that

down somewhere Scratch paper in your arms whatever we want

to keep track of where this variable takes us Line

two initiates a wild loop which will run as long

as an injured eye remains greater than zero so it's

five now and so it looks like we're good to

go Line three homeboy line three starts another loop nested

inside the first one and this time it's A four

loop Well four loops have three parameters The first being

the initialization imager J is one which is what we'll

be using is the eatery So write that on your

arm or whatever too The second is the termination parameter

When this condition is false the loop will no longer

run Yes j No longer being less than or equal

to I will stop the looting The third parameter is

called the increments and living up to its name It'll

increments j by one Each time the loop cycles Line

four is inside the loop It friends the product of

three times j and its base and he'll do it

over and over and over over within this loop until

j is no longer less than or equal to ay

well first time it runs Jay is one so we

print the product of three times one in a space

Then it'll increase j by one and a loop will

run again so next time it'll be three times too

and a space and then three times three and space

and three times for anna's face and three times five

in space And now jay six which is greater than

i look at your arms eyes five at the moment

That's the necessary condition for our four loop determining through

the chapel So now we move on to what happens

after the four loop which is an empty print line

statement that'll give us a new line and we subtract

one from i you all right But we're not done

The wild loop is still running And this time i

is for the interior Four loop is going to run

again and again until j is greater than i So

jay starts over at once and we'll print three times

one into space and three times do in the states

hand three times three spaces and three times for in

space but now has five which is greater than i

So we stopped the loop here and continue on with

an empty print line statement and decreasing i yet again

So from here we can totally tell what these loops

are doing and predict what will happen next The lupul

print three six nine and stop it because i will

be three And the local run again printing three six

and three At that point the wild loop will cease

running because i will no longer be greater than zero

Got all that and it looks like the result matches

up with the answer E and yeah that's our answer

and here's your smoke do sure brought to you by 00:04:37.173 --> [endTime] loops Wait not again Allright we're good out No