TAL Reference Manual

TAL Reference Manual—526371-001
3-1
3 Data Representation
Data is the information on which a program operates. Your program data includes
variables and constants.
Variables hold values that can change during program execution. When you declare a
variable, you specify a data type that determines the amount of storage the variable
requires, the kind of values it can represent, and other characteristics.
Constants are values that do not change during program execution. The compiler
determines the data type of constants from their size and format. You can assign
constants to variables. You can declare LITERALs, which associate identifiers with
constants.
This section describes:
•
Data types of variables and constants
•
Storage units in which you can access variables
•
Syntax for character string constants, numeric constants, and constant lists
Data Types
When you declare most kinds of variables, you specify a data type. The data type
determines:
•
The kind of values the variable can represent
•
The amount of storage the compiler allocates for the variable
•
The operations you can perform on the variable
•
The byte or word addressing mode of the variable