Chapter 6: Nested if Statements and Logical Operators

Overview

Chapter 5 began with the opening words of the famous poem The Road Not Taken by Robert Frost: Two roads diverged in a yellow wood, and sorry I could not travel both.

Not to be a poetry critic, but often there are more than two roads.

In Chapter 5, we evaluated only one Boolean expression at a time, and chose which of the two roads our code would travel down depending on whether the expression was true or false. However, sometimes two (or more) Boolean expressions need to be evaluated to determine the path the code will travel.

For example, you are eligible to vote only if you are a citizen and you are at least 18 years old. You cannot vote unless both conditions are true. Other times with Boolean expressions, you are testing if either of two comparisons is true. For example, you may get into a movie free if you are either a senior citizen (65 years or older) or a child (12 or under). Thus, you get in free if either condition is true.

This chapter will cover two different approaches to evaluating two Boolean expressions to determine which code should execute. The first approach nests one if statement inside another. The second approach introduces another type of operator: logical operators.