Lexical Scope

In our program for computing the square root of a number, we are using the variable x over and over again. We are defining it in each function even though it’s the same variable throughout the program.

In a previous lesson, we learned that definitions outside a block are visible to definitions inside a block unless they are being shadowed. The process of setting the scope of a variable is known as Lexical scoping and we can use this convention to remove the redundant x variables in our square root program.

Let’s first take a look at the original program.