Constants are Global

pivopen pivopen
May 2, 2025 - 12:22
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Yes, constants are typically global in many programming languages by convention, though the behavior can depend on the language you're using. Here's what that usually means:

1. Global Scope

Constants are often declared in a global or module-level scope so they can be accessed from anywhere in the program. For example:

python
PI = 3.14159 # Python convention for constant def area(radius): return PI * radius ** 2

2. Immutability

While the term "constant" implies immutability, not all languages enforce it. Some use naming conventions (like ALL_CAPS) to indicate a constant, but the value can still technically be changed unless enforced:

  • Python: Constants aren't enforced — it's a naming convention.

  • Java/C++/C#: Use final, const, or readonly to enforce immutability.

  • JavaScript: Uses const for block-scoped constants.

3. Best Practice

Declaring constants globally ensures they are:

  • Easy to maintain and update.

  • Reusable across multiple functions or modules.

  • Defined in one place, promoting cleaner code.