Constant is a data whose value cannot be changed during the runtime. Using a constant in a program consumes no RAM memory. Constants can be used in any expression, but cannot be assigned a new value.

Constants are declared in the declaration part of a program or routine. You can declare any number of constants after the keyword const:

const constant_name [as type] = value

Every constant is declared under unique constant_name which must be a valid identifier. It is a tradition to write constant names in uppercase. Constant requires you to specify value, which is a literal appropriate for the given type. type is optional and in the absence of it , the compiler assumes the “smallest” type that can accommodate value.

  Note : You cannot omit type when declaring a constant array.

Here are a few examples:

const MAX as longint = 10000
const MIN = 1000      ' compiler will assume word type
const SWITCH = "n"    ' compiler will assume char type
const MSG = "Hello"   ' compiler will assume string type
const MONTHS as byte[12] = (31,28,31,30,31,30,31,31,30,31,30,31)

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