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ZBasic Language Reference
17
ZX Microcontroller Family
Private Const Pi as Single = 3.14159
Const TwoPi as Single = Pi * 2.0
You may also use certain System Library functions in the constant’s value expression. The restriction is
that the expression must be able to be evaluated at compile time.
Private Const Pi as Single = ACos(-1.0)
Private Const InitialValue as Single = Sin(Pi / 2.0)
The definition of the value of pi in the manner shown in the first example is useful because it results in the
maximum accuracy of the constant value.
String constants are sometimes useful as well.
Public Const VersionNum as String = "V1.0"
Public Const VersionDate as String = "Oct 2005"
Public Const VersionStr as String = VersionNum & " " & VersionDate
Public Const VersionDateUC as String = UCase(VersionDate)
You may define multiple constants of the same or different types on the same line.
Const c1 as Integer = 7, c2 as Single = 3e10
BasicX Compatibility Note
In BasicX mode, UnsignedInteger, UnsignedLong and String constants are
not supported. Also, constant expressions cannot utilize built-in functions.
Defining Variables
To define a variable at the module level (as opposed to within a subroutine or function, described later)
the syntax is:
{Public | Private | Dim} <name> As <type>
Dim has exactly the same effect as Private, i.e., the variable will only be directly accessible to code
within the module.
Examples
Dim ival as Integer, pulseCount as Byte
Private busy as Boolean
Dim msg as String
The first example above shows two different variables being defined on the same line.
The initial value of a variable depends on its type and how it is defined. See Section 2.12 for information
on variable initialization.
Defining Arrays of Variables
Variables which hold a single value like those discussed above are called scalar variables. ZBasic also
supports arrays of variables. An array of a fundamental type may be defined using the syntax:
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