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In This Chapter

4.1 Constants ..................................................................... 15

4.2 Variables...................................................................... 16

4.3 Expression and Operators............................................ 17

4.4 Operator Precedence.................................................... 19

4.5 Labels........................................................................... 20

4.6 Subroutines .................................................................. 20

4.7 Programming Style ...................................................... 21

4.1 Constants

Constants are the actual values that BASIC uses during execution. There are two types of

constants:

 String

 Numeric

4.1.1 String

A string constant is a sequence of up to 250 alphanumeric characters or symbols enclosed in

a pair of double quotation marks.

 "Hello"

 "$20,000.00"

 "12 students"

4.1.2 Numeric

Numeric constants include positive and negative numbers. Numeric constants in BASIC

cannot contain commas. There are three types of numeric constants that can be used in the

BASIC Compiler:

C H A P T E R 4

Basics of the BASIC Language

1 2 ... 16 17 18 19 20 21 22 23 24 25 26 ... 197 198

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Metrologic IS1000 Series Guia do Utilizador Página 21