This statement declares constants for use in place of literal values.
[Public | Private] Const constname = expression
Constants are public by default. Within procedures, constants are always private; you cannot change their visibility.
To combine several constant declarations on the same line, separate each constant assignment with a comma. When you combine constant declarations in this way, the Public or Private keyword, if used, applies to all of them.
You cannot use variables, user-defined functions, or intrinsic functions, such as Chr, in constant declarations. By definition, they cannot be constants. You also cannot create a constant from any expression that involves an operator; that is, only simple literal constants are enabled. Constants declared in a Sub or Function procedure are local to that procedure. A constant declared outside a procedure is defined throughout the module in which it is declared. You can use constants anywhere you can use an expression.
Constants can make your code self-documenting and easy to modify. Unlike variables, constants cannot be changed inadvertently while an application runs.