Local and Global Variables

The body of a function is a code block that can contain valid statements, one of which is a variable definition. As we learned in Lesson 1, Getting Started, when such a statement appears, the function declares a local variable.

This is in contrast to global variables, which are the variables that are declared outside of functions (and classes, which we will look at in Lesson 3, Classes).

The difference between a local and a global variable is in the scope in which it is declared, and thus, in who can access it.

Note

Local variables are in the function scope and can only be accessed by the function. On the contrary, global variables can be accessed by any function that can see them.

It is desirable to use local variables over global variables because they enable encapsulation: only the code inside the function body can access and modify the variable, making the variable invisible to the rest of the program. This makes it easy to understand how a variable is used by a...