Original subtitles

Alright here's an exercise for you

I want you to write a function that takes two numbers and returns

the maximum of the two. Call that function, give a different

argument, and make sure it's working properly. So pause the video,

do this exercise, and when you're done come back and continue watching.

I'm going to start by defining a function, call it max,

here we need two parameters, we can call them number 1, and

number2, or we can use shorter names like

a, and b, now earlier I told you not to use

mysterious variable names like a and b, but in this particular case

doesn't really matter, because a and b are kind of self explanatory, so we are not

dealing with a complex logic, we don't have to guess what a and b

are as you will see in a second. So in this function,

you want to have some logic, we want to compare the value of a with b, so we're

gonna use an if statement, so if

a is greater than b, we want to return

a. else you want to return b.

That's the simplest implementation, it's not the best way, we're going to optimize

this step by step, but before going any further, let's make sure

that this function actually works. So I'm going to declare

a variable called number and set it to max of

1 and 2. Now let's display number on the

console. Save the changes, so

max is 2, so if the second argument is greater,

our function works, what if the first argument is greater, so

let's change 1 to 3, save, now we see 3,

perfect, what if both arguments are equal,

once again, save the changes, we still see 3, perfect,

now before going any further, did you notice how I called this function

with different arguments, I called it with different test cases.

First I assume that the second argument is greater,

then I assume if the first argument is greater, and finally I assume

that both arguments are equal. So when writing code, when writing functions,

you should test your functions with different possible values, okay?

Now, let's get back to this max function and clean up this code.

But first thing I want to improve here is to remove

this else keyword. Why? Because of 8 is greater

than b, we're going to return a, so we'll jump out of this function.

So none of the code after line 6 will be executed, in fact,

it will never get to this point, so we don't really need the else

keyword. Okay? So if a is greater than b, we'll

return a, otherwise we'll return b. So this is a

cleaner implementation. But hey we can make this even cleaner. So earlier

we learned about the conditional operator. Remember this?

So we add a condition in parenthesis.

Question mark, if this question evaluates to true,

we use 1 value, otherwise we use the other value.

We can rewrite these two lines, using our conditional operator

so what is the condition here? If a is greater than b.

If this condition is true, we want to return a,

otherwise we want to return b. All we need here is

a return statement and terminate this with a semi colon.

So, this line is exactly equivalent to these two lines.

Now, save the changes,

both arguments are equal, you get 3, so far so good,

let's try another test case. I'm going to make the first argument

larger, let's say 5, we get 5,

now let's make the second argument larger, 10, beautiful.

So our function is working.