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‫Some people say it's all about decisions in life.

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‫I say it's all about decisions.

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‫And C-sharp and that's what we're going to look at.

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‫We're going to check out if statements and they help us to make decisions and run code based on those

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‫decisions.

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‫And what we do here is we have an if statement.

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‫So this is a very basic if statement where we have a condition within curly brackets and then where

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‫we have a condition within brackets.

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‫And within the curly brackets, we have the code that should be run if the condition is met.

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‫So let's say we check if the weather is good and if it's good, then we want to go outside.

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‫And if it's bad weather, then we stay inside.

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‫So the condition would be, is weather good or is the sun shining?

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‫So that would be a very simple condition here where we simply compare if this is weather great or the

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‫sun is shining or something like that is true, and if it's true, then run the code.

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‫If it's not true, don't do anything.

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‫So that's what this statement would do, but it can be a bit more complex.

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‫So we can go ahead and have an IF statement with an LS statement.

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‫So if condition is met, run some code and if it's not met, so else in any other case, go ahead and

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‫run some other code.

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‫So if none of the conditions is met, then the LS statement will be run.

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‫And we have a prioritization here.

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‫So if this first condition is true, this else will never be true and it will never be run.

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‫And it's even more important if we check out the next step because we can have something called ls.

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‫If so, if condition one what to do?

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‫If condition is met else, then that's the default state.

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‫So if none of the conditions is met and then we have a different aspect here to consider, which is

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‫else if and we can have multiple ls if within one bigger if statement.

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‫So we have if condition one what to do if condition is met then we have ls if condition two what to

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‫do if condition two is met.

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‫So the first condition could be Sun is shining.

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‫All right.

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‫If sun is not shining, it could be the sun is not shining.

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‫Okay, we know that.

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‫But then we check.

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‫The second condition, for example, is the weather at least warm or is it at least plus 20 degrees

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‫Celsius?

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‫Then we would go outside still because we don't care.

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‫Then we just put on the jacket and we go outside.

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‫So that would be the second condition.

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‫But if none of those are met, so if the sun is not shining and it's freezing outside, then we go into

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‫the LS and we say, Oh, I'm going to stay at home, I'm going to drink a cup of tea and I'm just going

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‫to chill in front of the TV.

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‫So that would be an example of an if ls if on L statement.

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‫So you've seen the syntax and it makes a lot more sense once we get into the demo.

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‫So I'd say let's go ahead and have a quick demo where we simply are going to look at.

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‫If so, we're not going to look at the other aspects we're just going to use if for now.

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‫All right.

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‫So let's go into C-sharp and into Visual Studio.

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‫All right.

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‫So that we are let's go ahead.

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‫So I'm going to create a variable which is going to be an integer, and I'm going to say that that's

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‫the temperature temperature.

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‫And I'm going to set that to, let's say, ten degrees Celsius.

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‫So now I want to check if the temperature is below ten degrees.

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‫And if that's the case, I want to put on a code.

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‫So I'm going to write onto the console right line, take the code.

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‫Now, if the temperature is ten degrees, then I want to write something like

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‫it's ten degrees

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‫C, so ten degrees Celsius.

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‫And now finally, if temperature is higher than ten, I just want to tell something like cozy, warm,

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‫even though that's not really the case because it's pretty cold with ten degrees.

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‫But still I just chose ten degrees.

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‫So let's check it out.

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‫By the way, we need to add the console, right, to get anything onto our console.

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‫So let's do that and let's run our code.

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‫And it's going to say it's ten degrees.

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‫Why is that?

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‫Because that condition is not met.

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‫That one is not met, but this one is met.

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‫So let's say we take a temperature of six degrees and we run the same code and it says, take the code.

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‫All right.

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‫Now, let's say we have a temperature of 25 degrees.

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‫And it's going to say cozy and warm.

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‫Great.

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‫So now a little, little challenge for you.

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‫Please edit the code so that it says or takes the weather into consideration and you can enter the weather

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‫manually.

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‫And it also is going to tell you if you should take the code, if you should go in shorts, or if you

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‫should go like with a pullover and pants or something like that.

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‫All right.

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‫So just check that out and just change the code a little bit and then we will see the result.

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‫So please go ahead and try that.

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‫By the way, you should check out check the weather out outside and check the temperature and enter

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‫that.

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‫If you have a Fahrenheit temperature, then just use Fahrenheit values here.

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‫That makes sense.

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‫All right.

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‫I hope you tried it.

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‫And it's console dot red line what we need here.

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‫So we're going to read in the line that the user has entered and it's going to be a string, of course.

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‫So the temperature is going to be a string.

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‫Now we need to check and change the temperature into an integer.

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‫So int num temp.

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‫So I'm going to call it and it's going to be in 32.4.

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‫Actually int is good enough int parse temperature and now I can compare the num temp to let's say 20.

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‫So if it's lower than 20, if it's just 20 or maybe even if it's higher than 20.

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‫So this would be the right fit, I'd say.

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‫All right, so what I want to change the text to is, well, if it's below 20, take the code.

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‫If it's 20 degrees, then just write something like pants and pullover should be fine.

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‫And then finally, if it's higher than 20 degrees of it's warmer then.

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‫Right.

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‫Something like shorts are enough today.

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‫All right, so now let's check it out.

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‫Let's see what our program has to tell us.

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‫And I'm going to enter, let's say, 25.

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‫And it says Shorts are enough today.

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‫Maybe we should enter a little text here which tells us what to do.

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‫So console, dot, right line, what's the temperature like?

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‫And I'll start it again.

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‫What's the temperature like?

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‫I'm going to say, all right.

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‫Well, outside it's eight degrees.

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‫Take the code.

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‫All right.

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‫I'm going to take my code.

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‫It's fine.

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‫Thank you very much.

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‫So now we have a little program which is going to help us to decide what to wear based on the temperature.

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‫Isn't that great?

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‫So we have our first little program which actually has used or which is useful.

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‫Yeah, of course you can go ahead and extend that a little bit.

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‫And while that does work, this if if if approach here it's not the cleanest and we will see how we

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‫can clean that up in the next video, how to make it even better and more effective, because currently

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‫it's running this code, then it's running that code and then is running that code.

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‫But the better approach would be to check if that's true.

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‫Well, then the other ones can't be true.

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‫So don't even bother running that code.

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‫I told you about this approach not being super efficient, and I'm going to show you how to make it

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‫more efficient, because what we have seen is if else, if and finally else.

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‫All right.

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‫So you have seen that in the first video of this chapter.

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‫And now let's change the code that we have here to fit that structure.

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‫You can try it yourself so you can pause the video and try to fit that as well.

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‫Otherwise, just take a look at how I do it.

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‫All right.

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‫I hope you tried it.

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‫So we check if the temperature is below 20, and then if that is true, then that will never be true.

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‫So we won't need that code in case that is true, because it will just run and it's just unnecessary

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‫processing power that we need.

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‫But if we use ls instead so else if for example, then this code will only be run if that code here

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‫is not true, or if that condition here is not true.

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‫So now, if the temperature is not 20 or below 20, then we run that code.

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‫If it's not below 20, then we go to the next line and we check is the temperature exactly 20.

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‫And then we could go ahead and say something like else if and check for the next line.

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‫So if temperature is higher than 20, then do that.

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‫But that again would not be the most efficient way while it would work.

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‫A more efficient way is simply to just use less here, because if that condition is not met and that

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‫condition is not met, then that condition will run or the LL statement will run.

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‫Because in our case it's pretty simple.

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‫There are only those three options.

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‫It's either below 20, exactly 20 or higher than 20.

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‫Of course, we could other we could add other conditions like else.

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‫If num temp is equal to 30, we could add that and that would be fine as well.

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‫Then we will still have the condition of ls.

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‫That means that all the other code.

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‫So 21 to 29 would not be covered.

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‫They would be covered by this ls and everything higher than 31 would be covered by this.

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‫LS So we could approach that way or approach it that way, and then we could also have this higher than

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‫30.

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‫So if the temperature is higher than 30, then this code will be run, which would be, for example,

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‫it's hot or it's super hot.

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‫And all the other situations are so between 21 and 30 with this L statement will be run.

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‫All right.

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‫So these are the different options that we have, and this is a more efficient way than the one that

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‫we have just seen.