Chapter 2

Literal constant

A literal constant is a value you type into your program wherever it is needed.

Defined constant

Named constants must be assigned a value when they are defined. Variables do not have to be assigned initial values. Variables once defined may be assigned a value within the instructions of the program.

Constant

a value that cannot be altered by the program during normal execution, i.e., the value is constant; a data item whose value cannot change during the program's execution. Thus, as its name implies - the value is constant.

Variable

an identifier with a value that can be changed during normal execution, i.e., the value is variable; a data item whose value can change during the program's execution. Thus, as its name implies - the value can vary.