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As mentioned before, you can return values from a function.

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It is bad practice for your function to handle the final result, but it is good practice for your function

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to return the final result.

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So in this lesson you will create a function that returns a string.

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You have been provided with a text file.

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Please download it from your resources folder.

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Start by copying and pasting the following text underneath your return values class.

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Highlight it if you're using a mac press command slash.

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If you're using Windows Press control slash to comment out the text and now we can begin.

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All right.

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We will use the same function signature as before, but this time our function will be returning a string.

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So we specify a return type of string and the function name will be explained area.

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The function expects to receive a language value when called.

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So we define one language parameter of type string.

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All right.

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You'll notice right away that we get an error.

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The error is that the method must return a result of type string.

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But right now, our method is not returning anything.

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So in order to adhere to the return type, we need to return a string value.

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So we will return.

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Hello.

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And now whenever we call the function, it's going to return a string of hello.

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But that's not what we want to do.

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What we want is to compare the language that gets passed in.

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Against three possible cases.

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So the first case is if the language that was passed in is English.

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In which case we can return.

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Area equals length times width.

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If the language that they pass in equals French, then we can return.

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The following.

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If it's Spanish.

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Then we can return the Spanish text.

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You'll notice that this time we don't need to put the brake forward.

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Why do you think that is?

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To put it simply, while brake would only brake, the switch statement return would break the entire

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function when invoked.

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So you do not need to put brake after returning a value.

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It's going to return the corresponding value and immediately break the entire function.

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All right.

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But now you'll notice we still have an error here that says this method must return a result of type

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string.

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That is really weird.

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If the case is English, we're returning English text.

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If the case is French, we're returning French text.

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And if the case is Spanish, were returning Spanish text, but the function needs to return a string

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no matter what.

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Otherwise, it's going to throw an error.

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So we did not account for the scenario where a user might say case Italian if they put case Italian.

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None of these cases are going to get executed and the function is not going to return anything, but

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it needs to return a string no matter what.

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So what we have to do is say default, default account for every other scenario that doesn't match these

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three.

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In that case, we can return.

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Language not available.

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So whenever you specify a return type, you need to make sure that something gets returned no matter

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what gets passed in.

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Here we have a return type of double.

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This function is always going to return a double no matter what.

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Here we have a return type of string.

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The function is always going to return a string no matter what the scenario may be.

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Now the error is gone, which means we can start playing around.

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So here I'm going to say string English explanation.

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Is equal to whatever the explain area function returns when we pass in a language of English and we

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will copy this for more times.

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String French explanation will equal whatever explain area returns when we pass in a language of French

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string.

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Spanish explanation will equal whatever explain area returns when we pass any language of Spanish and

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string.

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Italian explanation will equal whatever the explain area function returns when we pass any language

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of Italian.

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And now what we're going to do is visualize the runtime.

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But starting from line number seven.

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So put a breakpoints here.

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Make sure that you have launched the exact folder that contains your Java file.

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Otherwise, visualizing the runtime might not work for you.

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And now we can go ahead and press the familiar debug button.

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So all of this code ran naturally because we didn't have any breakpoints here.

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And you can see that each area variable stores a different value depending on what was passed in in

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its respective function call.

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And now we move on to line number seven here.

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We're calling explain area passing in a value of English.

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Once you press, step inside.

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Now we can keep pressing step over.

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In fact, I recommend you do so.

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Otherwise you're going to be taken to the string class and we don't want to deal with that.

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In fact, take it as a rule of thumb, But once you already step inside the function, then you can

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just keep pressing step over.

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So we're going to press step over and the matching case is English return.

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What it's going to do is it's going to return this string.

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And as soon as it does that, it's immediately going to break the entire function.

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The explained area function call retained the value that was returned.

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And here we're setting the English explanation variable equal to that return value.

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Moving to the next breakpoint here, we're calling the explained area function again, this time passing

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in a value of French.

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The parameter stores the value that was passed in.

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And here we can compare that value against three possible cases.

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The case match is case French.

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As soon as the return keyword gets invoked, it's going to return the following string.

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And as soon as it does return the string return is always the last thing that ever runs any function,

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so it's automatically going to break the entire function.

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The explained area function call retains, it holds onto the value that was returned, which were then

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storing in a string variable French explanation.

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All right, now we have two variables, each one equaling a different explanation depending on what

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was returned by the function when it was called.

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And now we can just press continue.

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The Spanish explanation equals the Spanish explanation that was returned by the function.

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And Italian explanation is going to equal.

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I should have pressed step over instead of continue, because then it just continued to the next breakpoint.

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There was no breakpoint and I just terminated the runtime.

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So let me re visualize the runtime only putting a breakpoint at line number ten.

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I'm going to step over this line instead of continuing execution.

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The Italian explanation variable equals whatever was returned by the function when it was called.

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We can assume the default case was the one that executed returned a value of language not available.

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The function call held onto the returned value, which was then stored in a variable called string Italian

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Explanation.

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All right, we just created another function, but this one returns a string and this one returns a

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double.

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But I find this function much more interesting because we've got some conditional logic going on in

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here.

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Let us apply some conditional logic in here as well.

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So in real life, you would never have a negative length or a negative width.

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So what we can say is if length.

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Is smaller than zero.

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Or if the width is smaller than zero, then clearly the values that they passed in are invalid.

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So we're just going to say System.out.println in valid dimensions.

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And then we can say system.

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Dot exit zero.

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So if one of the values that gets passed in is negative, then we're going to print out a message telling

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whoever called the function that they messed up and we're going to terminate the runtime.

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So we will call the function again, this time passing any value of negative five and a width of, you

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know what?

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We will keep the width valid.

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All right, Let me just put a breakpoint over here.

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Debugging the runtime.

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Stepping inside of calculate area.

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So this if statement will only execute if the length is smaller than zero or if the width is smaller

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than zero, the length is negative five, which means this is going to evaluate to true.

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Because one of the comparisons is true.

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This entire condition is going to become true courtesy of the ore operator, which means it's going

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to print invalid dimensions.

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And it's going to terminate the runtime.

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All right.

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That is all you created functions that return values.

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In order to do a final recap, let us visualize the runtime everywhere.

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So first we're calling the function calculate area passing in two values.

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The parameter length stores.

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The first value that was passed in the parameter width store is the second value that was passed in

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here.

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We're checking if one of these values is less than zero, but because none of these are zero, both

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of these are going to evaluate to false, which means the entire condition is false.

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So this will get skipped.

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Here.

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It calculates an area that equals 8.28.

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Here we are returning the area.

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The function call holds on to the area value that was returned, which were then storing in a variable

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called area one.

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Here.

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We can just continue to the next breakpoint.

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Area two equals 3.84.

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Area three equals the value that was produced by the calculate area function when we passed in these

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values.

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And now here if we step inside.

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Unfortunately, the length equals negative five, which means this will evaluate to true meaning.

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The entire condition is going to become true courtesy of the operator.

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It's therefore going to print invalid dimensions and our application will terminate right here and now.

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But if we were to comment this out, we visualize the runtime.

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Continue.

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Continue, continue.

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Each area store is a value that was produced by the calculate area function depending on what was passed

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in.

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And here we can press continue.

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Continue, continue.

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Stepping over the final line.

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And here every string variable equals a string that was returned by the explained area function depending

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on which value was passed in.

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All right.

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That is all we're going to cover for return values.

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I really hope you've been enjoying these breakpoint sessions.