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‫Welcome back.

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‫In this video, we are going to have a look at four loops.

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‫Therefore, I'm going to show you the practice of using for loops.

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‫And we are going to start with an example.

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‫So let's go ahead and use the for keyword.

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‫Then in parentheses you have three values or three parts.

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‫So the first part is the counter itself and I use an integer here that's common practice and counter

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‫could be a name.

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‫Usually what you see is I so int I is something that you see quite often when seeing for loops.

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‫So counter then the condition here you compare your counter to a specific value.

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‫So let's say as long as counter is lower than ten, I want to go ahead and run my code.

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‫But now my counter needs to be initialized as well.

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‫So I need to set it, for example, to zero.

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‫So now the counter will run until it's nine because at ten this condition is not met anymore.

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‫So what I finally need is a increment.

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‫So I'm going to increment my counter by one by using the double plus.

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‫So by plus plus I say, okay, increase this counter by one as soon as this iteration of the for loop

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‫is done.

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‫And that's going to happen every single iteration.

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‫So every single time the for loop is run, it will increase by one.

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‫And we can simply see if that's true by using console dot right line.

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‫And here I'm just going to print out the counter.

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‫And now finally we need to use the console that read in order to see something on the console.

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‫So I'm going to run that real quick and then I'm going to go through what we see here once again.

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‫So let's look and we see 012344529.

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‫So it has run ten times, it started at zero and then it went all the way to nine.

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‫So that's what this counter does here or this for loop does here.

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‫So we have a start value which is of type integer and which I call the counter.

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‫Then after the semicolon we have the condition, so we check if counter is lower than ten and then we

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‫increase by one.

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‫So what the general flow here is we set a value to zero or to any other start value.

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‫Then we check if the condition is true.

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‫If that's true, then this code will be executed.

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‫So anything that's inside of the code body or the for loop body will be executed.

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‫Anything that is between those curly brackets.

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‫And in our case, it's simply to write something onto the counter.

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‫And then once that is done, once this part here is executed.

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‫So everything in the body, the counter is increased by an amount, and in this case it's increased

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‫by one.

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‫So it's incremented by one because counter plus plus increments a value by one.

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‫If you want it to decrease a value by one, you would use minus minus.

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‫But in our case, we want to increase it by one.

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‫So that's the general approach for for loop.

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‫Now let's have a look at a for loop which starts at zero, but goes to 50 and increments by five each

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‫time.

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‫So counter plus equals five.

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‫That means that it will increase its value by five each time it executed the code.

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‫So let's run it again.

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‫And that we are zero five, ten, 15 and so forth.

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‫So what our code does here is do the following.

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‫We start at zero.

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‫It checks is zero lower than 50.

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‫And that's true.

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‫So let's run the code so it executes and it writes zero onto our console.

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‫Then it increases itself by five, so it increments by five.

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‫The next time it checks, OC is five lower than 50.

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‫That is true.

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‫All right.

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‫So the run the code, then it's increased or incremented by five once again.

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‫So now it's ten.

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‫The counter checks is ten.

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‫Lower 50.

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‫Yes, it is.

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‫All right.

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‫Let's run the code and so forth until we are at the point where this condition is not met anymore.

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‫So let's say we were at 45 and now we increase the number by five.

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‫So we add another five, we increment by five.

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‫Then the condition here is not met anymore because it asks here or checks is 50 lower than 50 and because

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‫50 is not lower than 50 or smaller than 50, this condition is not met anymore.

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‫So the code is not executed anymore and we get outside of this loop.

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‫So we get to this code here, console read.

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‫So what we also could do just to see how that is true, we can simply write something like for loop

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‫is done and then we will see for loop is done.

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‫So after all of that is done.

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‫Condition is not valid anymore and it's done.

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‫We could even write something like counter plus is lower than 50.

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‫So now if we run it again, it says zero is lower than 50, five is lower than 50 and so forth.

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‫So this is the condition and it's met all the time and then the for loop is done.

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‫And that's generally how we for loop works.

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‫All right.

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‫Now a little challenge for you.

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‫Please go ahead and write a for loop, which only prints out the odd numbers from 0 to 20.

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‫So go ahead and build that.

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‫Just to counter my for loop counter, which only prints out the odd numbers.

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‫All right let's go ahead for and counter is equal to one counter lower than 20 counter plus plus and

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‫equal actually plus equal to.

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‫So we want to increase it by two each time.

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‫And now let's write that onto the console.

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‫So console right line.

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‫And here I write the counter and here again console, dot read and now we can go ahead.

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‫All right.

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‫And then we are all the old numbers.

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‫One, three, five, seven, nine and so forth.

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‫Great.

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‫So now you have seen how to create odd numbers and how to create for loops in general.

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‫And the next video, we are going to have a look at the do while loop.

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‫So see you there.