ENUM

• Source: https://www.freebasic.net/wiki/wikka.php?wakka=KeyPgEnum
• Last revised: 2021-12-13

---

Declares an enumerated type.

Syntax

Enum [typename [ Explicit ] ]

symbolname [= expression] [, ...]
...

End Enum

Parameters

typename

Name of the Enum

symbolname

Name of the constant

expression

A constant expression

Explicit

Requires that symbols must be explicitly referred to by typename.symbolname

Description

Enum, short for enumeration, declares a list of symbol names that correspond to discrete values. If no initial value is given, the first item will be set to 0. Each subsequent symbol has a value one more than the previous unless expression is given.

Symbols may be each on their own line, or separated on a single line by commas.

An Enum is a useful way of grouping together a set of related constants. A symbol can be accessed like a constant, e.g: a = symbolname. But if the name clashes with another symbol, it must be resolved using typename.symbolname. This resolution method is always required if you make the enum Explicit.

A non-Explicit Enum declared inside an Extern ... End Extern block will add its constants to the parent namespace directly, as in C, instead of acting as a namespace on its own. It disallows the typename.symbolname style of access, and the constants may conflict with other symbols from the parent namespace.

Enum can not contain any member procedure or member data (only symbols), but it can be included (named or unnamed) in a Type by having.

An Enum instance can be passed, as any user defined instance, to a procedure (including for the definition of Overloaded operators).

The size of an Enum instance will be always that of an Integer (no matter how many defined symbols are just declarations for the compiler assignment).

Examples

start GeSHi

Enum MyEnum
    option1 = 1
    option2
    option3
End Enum

Dim MyVar As MyEnum

MyVar = option1

Select Case MyVar
    Case option1
        Print "Option 1"
    Case option2
        Print "Option 2"
    Case option3
        Print "Option 3"
End Select

end GeSHi

You can reference formerly declared symbol names within the same enum:

start GeSHi

Enum MyEnum
    option1 = 1
    option2
    option3
    __
    MAX_VALUE = __ -1
End Enum

Print "Option #1:", MyEnum.option1
Print "Option #2:", MyEnum.option2
Print "Option #3:", MyEnum.option3
Print "Max Value:", MyEnum.MAX_VALUE

end GeSHi

Output:

Option #1:     1
Option #2:     2
Option #3:     3
Max Value:     3

Dialect Differences

• Explicit Enum not available in the -lang qb dialect unless referenced with the alias __Explicit.

Differences from QB

• New to FreeBASIC

See also

• Const
• Operator
• Table with variable types overview, limits and suffixes

Back to DocToc