Original subtitles

So another day, another challenge, right, guys, in this challenge, we proceed with practicing functions.

And the reason for that, for why I so much insist on practicing more and more exercises with functions,

is because this topic is actually so important.

And it will guide you during most of your programming career.

So pay close attention and let's go.

And what I want you to do in this challenge is simply to write a function that will receive a number

of an integer type.

And then the function is going to calculate its factorial.

And just a quick reminder, for those of you who is not familiar with water, if Victoria really means

and how it's calculated, the factorial of a given number is calculated by multiplying all the natural

numbers from one up to the given number.

So a factorial of NUM equals two one multiplied by two by three and so on up to the multiplication by

NUM.

All right.

In this case, we specified D as M name equals to M.

So for example, if you have a m to calculate the factorial of three equals two, one multiplied by

two multiplied by three, which is a total of just six.

And if you have to calculate the factorial of a number five, then you will say that eight equals two,

one by two by three by four by five, which is a total of one hundred and twenty.

Whoops.

Here I have only six.

That should be fixed to one hundred and twenty.

So basically you've got the point hand and that's my mistake.

I will fix it up.

So basically you multiply all the numbers from one, two, three up to the specified number to find

Edes factorial.

And then the function is going to return.

The result?

It will calculate the factorial and return the result.

And not printed to the screen, but rather it will return it.

So there we can check with the main function that it actually works as we expected it to work.

And that will basically bid for these function.

And one thing that I would like you to notice is that if then if a given number is going to be a negative

number, then the function will return minus one, because we cannot calculate a factorial for a negative

number.

And these minus one will specify that something something was wrong there.

And we will know how to treat it later on.

So good luck, guys.

Give it a try and I'll see you in the next video.