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Which demons can also give you control over your code, you learn to control which parts of your code

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run using, if elusive, and now statements, each statement has a condition and Java looks at the first

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statement with a true condition and runs the code inside.

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You can also use switch statements to control how your code runs.

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So in this lesson, you're going to learn how do you switch as well as when do you switch versus if

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else?

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First thing I'll need you to do is create a new class by yourself inside the Section three project,

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create a new file name, switch statements Java, and make sure the class has a main method.

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So how do you switch a switch statement compares one value against a list of values.

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In other words, it compares an argument against a list of cases.

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The argument is the value that you're comparing and if the argument matches value one, the first case

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runs, if the argument matches value to the second case runs, if the argument matches value three,

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the third case runs and if the argument matches none of the values the default case runs.

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And so back in our code, we're going to see this in action, we're going to make it into variable named

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and month and it's going to story value that represents a month five, which corresponds to the month

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of May.

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And so now we're going to make a switch statement and it's going to compare your month value against

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the list of month values in the form of cases.

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So we're going to rate case one.

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And there are 12 months, so we'll need 12 cases, so I'm going to copy this 11 more times.

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And I'm going to number each case in ascending order.

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Followed by default, now, if the argument month matches one of the cases, that case is going to run

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and we're going to need to print that month in text.

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So if the month ends up being equal to one, we're going to print January.

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If it matches, case two will print.

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And you know what, I'm just going to copy this Prince theme throughout.

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And now I'm going to fill in the appropriate month values.

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And if I were a month value doesn't match any of our cases, a default case should execute.

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And if it does, we're going to print please enter a valid month.

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They think we're ready to run our code.

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Whoa, that's weird.

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The month argument matches Case five, Jalaa clearly ran Case five, but it also runs every case that

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follows.

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Well, that's because by nature, which runs every case that follows the case much, it's like the switch

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turns on when there's a match.

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Let's have a look.

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You saw the value five in the month.

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Variable switch accepts your month value as an argument, and it compares it to a list of month values.

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It starts comparing your value against each case.

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Case one, two, three, four, five.

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Aha.

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We have a match.

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So the switch turns on and Javor runs case five, but it also runs every case that follows the case

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match.

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This is pretty frustrating.

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How do we fix it?

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That is exactly why we have the brake keyboard, the brake keyboard can break the switch statements.

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And so every case inside your switch them it needs to end with the keyword that way after your case

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runs, Java knows to break out of the switch statement.

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So back in our code, we're going to fix the switch statements.

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We're going to add the break keyword at the end of each case.

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And now we can rerun our code.

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And that's much better.

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So which compares your value against each case?

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Uh huh.

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We found a match after Jova runs the code inside case five, it then sees the break keyword and that

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breaks out of the switch statements.

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So why didn't we at break next to default?

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Well, default is the last thing that can run.

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Switch already breaks after default, but for the sake of example.

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We'll set month equal to some absurd number like 30 to.

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We'll rerun our code.

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And the month value doesn't match any of the cases, so the default case Rut's.

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All right, so it's time for the million dollar question.

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When do we use a Felsen?

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When do we use switch?

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I want to preface this by saying I use a false 95 percent of the time.

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And if statement can test any condition, a switch statement can only compare a value against the list

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of others.

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So we'll think back to the OP we just built, the one that grants diploma if a student has over 40 credits

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and a minimum GPA of 2.0.

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Can you think of a way to do this using such absolutely impossible GPA and credits can be any number

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from an infinite range of values.

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Are you going to make infinite cases?

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I don't think so.

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The way it fails is designed around conditions and ranges.

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It's way more flexible than comparing a value against the list of cases.

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So if you fast forward to the AP book just now, you can easily use it false.

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So why didn't we use them?

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We'll have a look at this code looks pretty ugly, doesn't it?

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Once again, the screaming cat is there to tell us what not to do if you're comparing one value against

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the list of other values, don't use a false uSwitch because it's honestly prettier.

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It's easier to read.

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And they also run a tiny bit faster than anything else in general.

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So if you don't want to get lost, just follow this rule of thumb and you should be golden.

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You can only use switch to compare one value against the list of others in any other scenario.

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And 95 percent of the time you're going to need efforts to control how your code runs.

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In this section, you learn to fully control how your code runs using NFLs and switch statements, if

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false runs a piece of code.

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If the condition is true, conditional statements, officials are way more flexible than switch statements.

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Ninety five percent of the time you're going to use efforts to control how your code runs.

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Switch runs a piece of code.

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If the argument matches a case on the off chance that you need to compare a value against a list of

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other values, then you can use switch.