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Welcome to a very, very important topic, which is the if else topic, i.e. conditional statements,



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are we doing something based on a condition that we are testing for?



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So let's begin let's say we have a VAR temperature is equal to 12 degrees that Celsius for all the Americans



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out there.



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I don't know what that is in Fahrenheit.



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No idea how to do the conversion, although we will have an idea how to how to do the conversion.



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If you're also taking my iOS development course, because we make a temperature converter app there,



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so you'll find out the answer there.



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What if I want to advise someone as to the clothing they should be wearing based on the outside temperature?



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So you might imagine this would be part of a weather app telling you what kind of clothing today is



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likely to require.



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We would say if the temperature is less than, let's say, perhaps five degrees.



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Then we'll print.



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Wear a big coat.



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It reminds me of a joke that runs between the north and south of the U.K., I currently live in Liverpool



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in the south, there's a weather report saying there are terrible storms tomorrow, awful rain.



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It's going to be freezing cold.



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We advise everyone to stay at home.



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Schools are closed and in the north exactly the same way.



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The report says you better take your big coat out tomorrow.



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That actually sums up the difference between the north and the south of England very, very well.



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It's a very interesting difference in the way that people look at life in the north and south.



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And I think in America, correct me if I'm wrong, it's the same difference between the northern or



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the maybe the coastal states and the interior states.



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Am I right in thinking that you're much more individualistic in the interior states versus the coastal



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ones?



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I could be wrong.



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Go ahead.



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Feel free to comment if I'm wrong.



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Anyway, let's get back to programming now.



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The beautiful thing of an if statement is we can have various conditions that we check through.



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So if something isn't true, there clearly were not below five degrees, then we want to check for something



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else else if the temperature.



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Is less than 15 degrees, we might say, Prince.



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Bring a jumper.



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Which is a jersey or sweat pants or whatever you want to call it in America, and then if we're anything



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over 15 degrees or else.



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It's T-shirt time.



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OK, so running through this, we go through conditions if we have an else, if right, so if it isn't



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caught here, it's going to fall through to here.



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If that isn't caught, it's going to fall through to as many else if statements as you like.



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Finally, if it gets through nothing and nothing matches, it can fall through to the statement which



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covers everything else.



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OK, now you don't have to have an EL statement, you don't have to have an IF statement.



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You can end the whole thing on just a single if statement.



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You can have any mix and match of these as long as you always start with an F.



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Now, if we run this, we should get bring a jumper and of course, if we increase the temperature to



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50.



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That's pretty hot.



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Wear a big coat.



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Ah, I've changed the wrong thing, haven't I?



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I've changed that to five waps.



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We should be changing this upper temperature.



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Let's change that to twenty three.



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It's T-shirt time, right?



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So that's the if else you're going to use this everywhere, absolutely everywhere.



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And so to set you on your way, we're going to have some homework create and if else, statement to



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call someone young, middle aged or old based on an age variable.



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Pretty straightforward.



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Good luck.