We can combine expressions containing logical operators to create even more complex Boolean expressions. When combining logical operators, the order of evaluation is as follows:

1. Boolean expressions contained within parentheses
2. NOT - !
3. AND - &&
4. OR - ||

Take a look at the following snippet of code:

var isSnowing = true
var isSunny = false
var temp = 38

if (!isSunny && (temp > 40 || isSnowing)) {
  println("Wear a coat.")
} else {
  println("Don't wear a coat.")
}

Let’s discuss the order in which this expression is evaluated. Here is the Boolean expression we are evaluating:

!isSunny && (temp > 40 || isSnowing)

(temp > 40 || isSnowing) is evaluated first because the expression is contained within parentheses. This expression results in true, making our expression look like this:

!isSunny && true

!isSunny is evaluated next because of the NOT operator. This expression is true because it negates the value of isSunny:

true && true

Finally, we evaluate the expression using the logical AND operator (&&). Since both sides of the operator have a true value, the expression inside our if statement is true and we get the final output:

Wear a coat.