There are two types of variables, what are they? What is the difference between these two types of variables?

In programming, variables can be categorized in many ways, but one common categorization is into two types: local variables and global variables.

1. Local Variables: These are variables that are declared within a procedure or a block of code. They are only accessible within the procedure in which they are declared. Once the procedure ends, the variable is destroyed and its value is lost. Each time the procedure is called, a new instance of the variable is created.

2. Global Variables: These are variables that are declared outside of all procedures, usually at the top of the code module. They are accessible from any procedure within the code module. Their value is retained for the entire duration of the program's execution.

The main difference between these two types of variables is their scope, i.e., the part of the program where the variable can be accessed. Local variables have a limited scope (only within the procedure where they are declared), while global variables have a wider scope (they can be accessed from any procedure in the code module).