Understanding Variables in Kotlin: Exploring the Differences Between 'const' and 'val'

 In Kotlin, both "const" and "val" are used to declare variables. However, they have different meanings and usages:

1. "val": The "val" keyword is used to declare an immutable variable, which means its value cannot be changed after it has been assigned. Once a value is assigned to a "val" variable, it remains constant throughout the program's execution. It is similar to declaring a final variable in Java or a constant in some other programming languages.

   Example:

   
   val pi = 3.14
   

   In this example, the variable "pi" is assigned the value 3.14, and it cannot be reassigned to a different value later in the program.

2. "const": The "const" keyword is used to declare compile-time constants. It can only be used for top-level or member-level properties, and the value must be known at compile time. Unlike "val" variables, "const" variables are replaced with their values during compilation, which makes them more efficient.

   Example:

   
   const val MAX_VALUE = 100
   

   In this example, the constant "MAX_VALUE" is declared with a value of 100. Since it is a compile-time constant, any reference to "MAX_VALUE" in the code will be replaced with the actual value of 100 during compilation.

It's important to note that "const" can only be used with primitive data types or String objects, whereas "val" can be used with any type, including user-defined classes.

To summarize, "val" is used to declare immutable variables whose values cannot be changed after assignment, while "const" is used to declare compile-time constants that are replaced with their values during compilation.