Why the setter function is not running in this Kotlin program - kotlin

Question

The following is the kotlin program. I have confusion that why the setter function is not being called on running line x.b=20.
class Num(value: Int) {
var a = value + 4
var b = value + 6
var c = value + 1
set(value) {
println("field is : ${field}")
field = value + b
println("field is : ${field}")
println("inside setter am here")
}
}
fun main(args: Array<String>) {
var x = Num(3)
x.b = 20
println(x.b)
}

Answer 1

It would be much clearer if your indentation were correct:
class Num(value: Int) {
var a = value + 4
var b = value + 6
var c = value + 1
set(value) {
println("field is : ${field}")
field = value + b
println("field is : ${field}")
println("inside setter am here")
}
}
You have only defined a setter on c. There is no way to make one setter for all the values, though factoring out a method might help.

Answer 2

Louis explained why it's not working, but this statement:
There is no way to make one setter for all the values
is not correct. It is possible by using delegated properties:
import kotlin.reflect.KProperty
class Num(value: Int) {
var a by MySetter(value + 4)
var b by MySetter(value + 6)
var c by MySetter(value + 1)
}
class MySetter(private var field) {
operator fun getValue(thisRef: Num, property: KProperty<*>) = field
operator fun setValue(thisRef: Num, property: KProperty<*>, value: Int) {
println("field is : $field")
field += value
println("field is : $field")
println("inside setter am here")
}
}
fun main(args: Array<String>) {
var x = Num(3)
x.b = 20
println(x.b)
}
This prints:
field is : 9
field is : 29
inside setter am here
29