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‫Welcome back.

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‫I hope you managed to get a solution for the challenge.

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‫And now let's go ahead and see how I would do it.

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‫Of course, there are multiple solutions to the challenge, and one of them is the one that I'm going

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‫to show you.

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‫So if you didn't manage to get that done, no worries.

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‫I'm going to show you in this video.

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‫So, first of all, what we need is an input variable and that one is going to be set to zero.

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‫Then we need the amount of entries.

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‫Or actually we could you call that count, which I set to zero as well.

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‫But this time it's an integer.

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‫Then we need to total, which I'm going to set to zero as well.

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‫And then we need the current number.

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‫Current number, and that one is going to be zero as well.

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‫So these are going to be the variables that are important for our following program, because what we

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‫need to check is what did the user enter or the teacher enter?

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‫Was it a number?

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‫If it was a number, we're fine.

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‫Then let's increase the total, let's increase the count and well, let's parse the input and add that

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‫to the total in general.

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‫And the current number is going to be the input as a number.

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‫So these are the four variables that are relevant here.

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‫So let's create a while loop because I want to see if the input is not equal to minus one.

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‫Because if that's the case, then that means that the teacher doesn't want to add any further values.

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‫Now let's inform the teacher first what is required of him.

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‫So let's write to him.

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‫Last number was and then we have, for example, here our zero and current number.

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‫So as we have not started well, as we have not entered anything yet, that's something that will be

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‫shown with zero at the beginning.

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‫So the current number will be zero.

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‫And that's just a text that the teacher gets to get informed about all the different states that are

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‫relevant to him.

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‫Then please enter the next score.

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‫That's just to inform him that she should enter scores.

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‫Then console right line once again.

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‫And now current amount of entries.

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‫So he knows how many entries he has made.

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‫And that should be again, our curly bracket zero.

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‫And then that will be the count.

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‫Now finally, console dot right line.

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‫We need to inform the teacher as well that if he enters minus one, the whole application will be done.

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‫Well, pretty much the calculation should be done and he gets the average.

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‫So please enter minus one.

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‫Once you are ready to calculate the average or once you have entered all the scores or something like

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‫that.

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‫So the text is what you of course have to choose yourself.

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‫What do you want to inform him about?

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‫Now we need the input, so let's get the input of the teacher and that's going to be console dot read

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‫line.

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‫Next, we need to check if the input is equal to minus one.

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‫So minus one.

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‫And we can either do that way or we can use the equals.

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‫Equals minus one.

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‫So what do we want to do if the teacher entered minus one?

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‫Well, we want to calculate the average.

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‫So let's go ahead, console right line.

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‫And what I want to do here is just for easier viewing pleasure or better viewing pleasure.

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‫To add this dotted line so that we can see this hash line, so that we can see the average a bit better

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‫and see that all the steps before are separated.

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‫Now we need to calculate the average of what was entered.

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‫And that's something that we can do later on, calculate average and let the teacher know.

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‫So that's something that we can do later.

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‫But now there are some other things that we need to do as well.

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‫So we need to, for example, check if the entry was actually a number.

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‫So int try parse.

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‫So if it worked that he parsed correctly.

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‫And what is it that we want to parse?

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‫Well, we need to parse the input and the output should be the current number.

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‫So if it did work, we want to have the current number to be the output, right.

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‫Next what we also want to check if the current number so current number is higher than zero and the

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‫current number is lower than 21, because I just assumed that the score that the user can get is between

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‫one and 20.

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‫So that's simply what I'm making sure of here.

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‫So I'm checking.

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‫Is it actually something that worked?

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‫So is it the number that he has entered and is the number between zero and or between one and 20?

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‫And if that's the case, please go ahead and add that to the total.

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‫So we have the total of zero so far.

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‫And what we want to have now is total equals total plus current number.

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‫So you can either do it that way, total equals total plus or you can plus equals current number.

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‫So that's the shorter approach.

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‫But the other one might be easier to read based on what you prefer.

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‫So that will be executed if it can be parsed into a number.

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‫So whatever the user has entered can be parsed into a number.

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‫What if it wasn't the case?

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‫So if it couldn't be parsed into a number or the number is higher than 21 or lower than zero, then

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‫we want to check first if the entry is not equal minus one, because if he has entered minus one, then

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‫we want to finish the program anyways.

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‫Right.

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‫So what we need to do here is to inform him.

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‫Console right line, please.

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‫Enter a value between one and 20 because this condition here will only be met if he entered something

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‫that is not between one and 20.

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‫So if it's a letter, if it's a whole text, if it's a different number like 25 or whatever, so that's

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‫what will be printed to him.

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‫And then if that happens, we want to continue.

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‫So we simply want to go to the next step.

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‫And now we need to run something within our wild code.

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‫So I'm going to make it a little smaller.

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‫So we have everything on one screen and now we need to add the amount of iterations.

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‫So here we need to increase the amount, which is our count.

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‫Okay.

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‫Amount of entries is our count, and I'm going to incriminate count here.

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‫Why do I increment it here?

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‫Well, I do so to make sure that it only is executed.

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‫So we only increment count if we actually want to increment the count.

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‫Because if you would do it without this, continue here, then it would even increase the amount of

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‫entries if the number entered was not between zero or between one and 20, or if it was a different

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‫kind of entry like the latter or something like that.

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‫So here we make sure, okay, it only gets executed if everything worked fine.

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‫So he entered a value that is good and we can go ahead.

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‫All right.

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‫So now one thing is left to do, and that is to calculate the average.

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‫And how do we do that?

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‫Well, we go ahead here.

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‫We create a double.

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‫And I use a double now because otherwise my average would be a whole number which is cut off and it's

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‫not as precise as I want it to be.

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‫So I'm going to call it average, which is a double of our total divided by a double of our count.

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‫So what I say here is that the average is the total amount which is here.

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‫Is incremented each time that we enter something.

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‫Divided by the amount of entries that we have.

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‫So that's basically the calculation or the formula to calculate the average.

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‫Right.

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‫Next, what we want to do is to write that onto the console.

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‫So let's write it like that.

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‫The average score of your students is and then we use the curly brackets zero again and hand over the

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‫average and that's pretty much it.

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‫So now we have our program which uses the input of the user and now we can go ahead and test that because

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‫we should.

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‫Oh, actually, we are missing one thing.

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‫We are missing the red line towards the end because otherwise we don't see the result here.

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‫So let's add that console that read or actually read.

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‫Read the red line doesn't matter as long as we still get to see the code.

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‫Let's run that.

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‫Last number was zero.

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‫Please enter the next score.

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‫Current amount of entry zero.

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‫Please enter minus one.

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‫Once you are ready to calculate the average.

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‫All right.

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‫Let's go ahead.

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‫Let's enter a just to check if our program still works.

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‫Please enter a value between one and 20.

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‫Perfect.

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‫Last number was zero.

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‫Please enter the next score.

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‫Current amount of entries is zero.

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‫So so far, everything is good.

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‫Even if we enter some gibberish here, it still works perfectly.

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‫So now let's enter ten.

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‫Last number was ten.

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‫Okay, now let's enter 15, 13, 12 and so forth.

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‫So I'm just going to add some numbers here.

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‫And if I add something like 31, it says, please enter a value between one and 20.

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‫That's good.

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‫So it knows if I do something wrong.

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‫So if the teacher accidentally enters values that are incorrect, it will be stopped here.

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‫So we have current amount of entries.

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‫11 So I'm going to enter minus one and let's see what happens.

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‫And it says the average score of your students is 11.09, zero nine, zero nine and so forth.

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‫Great.

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‫So here you see what we can do with the knowledge that we have gained so far.

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‫We can create little average programs and you can do a lot more.

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‫So we haven't seen how to use great user interfaces yet.

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‫We are still working with consoles, but we'll get there.

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‫So you will see how to create user interfaces with WPF, which is a tool to create great UI's with Visual

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‫Studio.

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‫So for now, I think that's good progress.

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‫And in the next video, we're going to go ahead with the next topic.

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‫So I hope to see you there and I hope you could solve that issue or that challenge or at least some

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‫of the challenge.

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‫And please let me know how you solved it so other students and I can compare what you've done and give

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‫you some feedback or compared to what we have created ourselves.

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‫So thanks a lot and see you in the next video.