Welcome back. So, we've already covered booleans which allow us

to write expressions that evaluate to either true or false.

But knowing if something is true or false isn't typically that useful on it's own.

Most of the time when we use Booleans,

we use them in combination with conditional execution.

Conditional execution allows us to say,

"Run this piece of code if something is true,

run this piece of code if something else is true,

or run this piece of code if something is false".

So, let's jump right into conditional execution.

So, we do conditional execution with if and else statements.

So, in this code,

we declare a variable X and set it here to the value 15.

Then, we say, if x modulo two equals equals zero.

As a quick reminder,

modulo is the remainder operator.

So, for example, if we take 15 modulo two,

then because 15 divided by two is seven with a remainder of one,

modulo gives us only are there remainder.

So, 15 modulo two is one.

If we did 14 modulo two,

then because 14 divides evenly into two,

a seven then we get a remainder of zero.

If we did 13 modular two,

then we get a remainder of one and so on.

So, in other words, if we take x modulo two,

then it's going to be zero if

x is even and it can be divided by two with no remainder,

and it's one if x is odd.

So, in this code,

we say if x modulo two is zero,

which to us this is a Boolean expression that's going to evaluate to

true if x is even and it's going to evaluate to false if x is odd.

So, we say if it's even,

then print out x is even then we say else,

so you can think of else as being like otherwise.

So else is saying otherwise if this condition is false,

then do something else.

So, we say if x is even,

print out x is even.

Otherwise, if x is not even,

print out x is odd.

So when I run this code while x is 15,

then we should expect this else condition to print out x is odd. So, let's run our code.