In Kotlin, var
and val
Both keywords are used for declaring variables.
var – Variable declare with var keywords are Mutable Variables, value of variable can be changed
fun main() {
var color = "Green"
color = "Red"
println(color)
}
/**
Output :
Red
*/
val – Variable declare with val keyword are Immutable Variables, this is read only variables. it’s not constant value. It is similar to final variable in Java.
fun main() {
val pi: Double = 3.14
val name: String = "Marsh"
println("The value of pi is: $pi")
println("My name is: $name")
// Compilation error if you try to reassign a value to a val variable
// pi = 3.14159
// name = "Jane"
}
Output :
The value of pi is: 3.14
My name is: John
Use Cases:
- Use
var
when you need a variable whose value may change during the execution of the program. - Use
val
when you want to declare a variable with a constant (unchangeable) value.