In Kotlin, a constant is a kind of variable that can not be reassigned after initialization. To declare a constant, you use the keyword val followed by the constant name, a colon :, and the data type that the constant will hold.
Here are a few examples of declaring constants in Kotlin:
// A constant holding an integer value
val number = 10
// A constant holding a string literal
val message: String = "Hello, World!"
// A constant holding a boolean value
val isTrue = true
// A constant holding a double value
val price: Double = 9.99
As you can see, once you initialize a constant, its value can not be changed. If you try to reassign a constant value, the compiler will generate an error. For example:
val myName = "John"
myName = "Jane" // Error: Val cannot be reassigned
Using constants can help you avoid accidental changes to values that should not be mutable in your program.