How can you declare a constant in Kotlin?

To declare a constant in Kotlin, the const val keywords are used. This combination is specifically designed for defining compile-time constants, which means the value is determined at compile time rather than at runtime. Using const ensures that the variable can only hold constant values that are known at the time of compilation, and it must be of a primitive type or String. This is particularly useful when you want to define constants that can be accessed from anywhere in your code, such as across different classes, while still adhering to Kotlin's type-safety and immutability features.

For instance, a declaration like const val MAX_LENGTH = 10 makes it clear that MAX_LENGTH is a constant and cannot be changed after it is declared. This provides clarity in your code and prevents accidental reassignments, which is a significant advantage of using const val over other variable declarations.