The {{KW|CONST}} statement globally defines one or more named numeric or string values which will not change while a program is running.


{{PageSyntax}}
: '''CONST {{Parameter|constantName}} = {{Parameter|value}}'''[, ...]


{{Parameters}}
* {{Parameter|constantName}} is the constant name or list of names assigned by the programmer.
* {{Parameter|value}} is the value to initialize the global constant which cannot change once defined:
** If {{Parameter|constantName}} specifies a numeric type, {{Parameter|value}} must be a numeric expression containing literals and other constants.
** If {{Parameter|constantName}} specifies a string type, the {{Parameter|value}} must be a literal value.


''Usage:''
* The {{Parameter|constantName}} does not have to include a type suffix! The datatype can be determined by the {{Parameter|value}}.
* Constant values cannot use a variable, [[SUB]] or [[FUNCTION]] return value when defined.
* Constants cannot be re-assigned values. They retain the same value throughout all of the program procedures.
* Constants defined in module-level code have [[SHARED|shared]] scope, so they can also be used in [[SUB]] or [[FUNCTION]] procedures.
* Constants defined in {{KW|SUB}} or {{KW|FUNCTION}} procedures are local to those procedures.
* [[CLEAR]] will not affect or change constant values.


''Example:'' Display the circumference and area of circles:
{{CodeStart}}' Declare a numeric constant approximately equal to the ratio of a circle's
' circumference to its diameter:
{{Cl|CONST}} PI = 3.141593

' Declare some string constants:
{{Cl|CONST}} circumferenceText = "The circumference of the circle is"
{{Cl|CONST}} areaText = "The area of the circle is"

{{Cl|DO...LOOP|DO}}
    {{Cl|INPUT}} "Enter the radius of a circle or zero to quit"; radius
    {{Cl|IF...THEN|IF}} radius = 0 {{Cl|IF...THEN|THEN}} {{Cl|END}}
    {{Cl|PRINT}} circumferenceText; 2 * PI * radius 
    {{Cl|PRINT}} areaText; PI * radius * radius ' radius squared
    {{Cl|PRINT}}
{{Cl|DO...LOOP|LOOP}}
{{CodeEnd}}
{{OutputStart}}Enter the radius of a circle or zero to quit? ''10''
The circumference of the circle is 62.83186
The area of the circle is 314.1593

Enter the radius of a circle or zero to quit? ''123.456''
The circumference of the circle is 775.697
The area of the circle is 47882.23

Enter the radius of a circle or zero to quit? ''0''
{{OutputEnd}}
: ''Explanation:'' PI cannot change as it is a mathematical constant so it is fitting to define it as a constant. Trying to change PI will result in a programming error.


{{PageSeeAlso}}
* {{KW|DIM}}, {{KW|SHARED}}
* {{KW|STATIC}}, {{KW|COMMON}}
* [http://doc.pcsoft.fr/en-US/?6510001 Windows 32 API constant values]


{{PageNavigation}}