Variables
Concrete concepts that are represented in a program are called variables. A value like air temperature and a more complicated object like a car engine can be variables of a program.
The main purpose of a variable is to represent a value in the program. The value of a variable is the last value that has been assigned to that variable. Since every value is of a certain type, every variable is of a certain type as well. Most variables have names as well, but some variables are anonymous.