AP Computer Science 2.4 Review of the Basics

APCS: Review of the Basics Drill 2, Problem 4. What is the output of the following code segment?

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Transcript

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and here the potential answers All right pausing thinking and

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we're going to answer this question We need to know

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what exactly an escape character or escape sequence is And

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when it's used Well this is one of those things

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that doesn't get used frequently but when you need it

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you'll wonder how you would have managed without it Yeah

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like knowing how to catch a fish with your shoe

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laces but not quite as dramatic In java a backslash

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followed by a certain character is called in escape sequence

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Let's suppose you want to print the following string in

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a program The sign at the door red no hats

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please but i wasn't technically wearing a hat It was

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a raccoon not wanting to cause trouble mr scratchy and

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on a left the interesting program you've got there The

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problem with throwing that string in a normal print statement

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is the quotation marks will confuse the compiler It believes

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the first quotation mark from no hats please is the

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end of the print statement after that it's expecting to

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see more code and when that doesn't happen the compiler

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will return an error There are a couple ways to

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solve this problem First one would be tio not where

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raccoon is a hat because second and more useful way

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would be to escape the quotation marks in the string

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So the compiler doesn't treat him like a code really

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by placing a backslash in front of the quotation marks

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we want to compiler to ignore We escape them and

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they'll get asked like right through the prince stay just

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like that though notice that we use the back slash

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on the apostrophe too that's to prevent it from being

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recognized as a single There are some special escape sequences

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to a backslash followed by an end will insert a

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new line at that position Backslash t will insert tab

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and there are a few others that are a little

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more obscure like this stuff Our question is asking us

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what will happen with the following print statement so let's

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look at the back slashes in the string The first

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one will ensure the apostrophe gets past and not confused

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for code So time will come out just fine Quotation

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marks around testing are also properly escape so those quotation

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marks will be printed correctly Then there's the backslash end

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which is we just learned prints a new line and 00:02:38.63 --> [endTime] that's answered