Constants

Constants are fixed values that will not change during the course of the program. These are useful when you want to name immutable values.

Constants can be most of Basic Data Types, excluding Pointer. Expression of constants must be evaluated during compilation.

The Const keyword is used to assign an identifier to a constant. For example:

Const width% = 640, height% = 480

You can then use the more readable width and height throughout your program instead of 640 and 480. Also, if you decide to change the width and height values, you only have to do so at one place in the program.

Attention

Using another constant in the constant expression is undefined behavior, since the initialization order does not depend on their order in the source code.

The example below shows this behavior. When the compiler initializes foo% before bar%, this code will work properly. Conversely, it causes a compiler error.

Const foo% = 100
Const bar% = foo