A variable is a named memory location which temporarily stores data that can change while the program is running.

A constant is a named memory location which temporarily stores data that remains the same throughout the execution of the program. 

The type of a variable indicates what kind of value it will store.

The name of a variable is known as its identifier.

A variable can be given a value through an assignment statement.

C++ recognizes eleven built-in data types which are designated by reserved words:

Variables of different types occupy different amounts of memory space and are described as having different sizes.

** The basic C++ types that are included in the AP Computer Science subset are int, double, bool and char.

Rules for assigning variables:

Assign short, int or long data types when you are sure a variable is an integer number (NO decimal points).  While these three integer choices are available, based upon the size of the numbers you are using, we will be using only int.

Assign float or double when decimals are needed.  We will primarily be using double, as suggested by the AP Computer Science subset.

Assign char if the variable will always contain ONE character of data.  This means only one letter (or character).