JuniorTheoryCommon

What happens when you build and run this program?

KOTLIN

fun addOne(n: Int): Int {
    n = n + 1
    return n
}

fun main() {
    println(addOne(5))
}

It does not compile: a parameter cannot be reassigned

Expecting 6: treating a parameter as a variable you may change. In Kotlin a parameter is read-only, like a val, so n = n + 1 does not compile.
Expecting the program to fail only when it runs: the compiler checks every assignment first and reports 'val' cannot be reassigned., so nothing runs.

JuniorTheoryCommon

KOTLIN

fun addOne(n: Int): Int {
    n = n + 1
    return n
}

fun main() {
    println(addOne(5))
}

It does not compile: a parameter cannot be reassigned

Expecting 6: treating a parameter as a variable you may change. In Kotlin a parameter is read-only, like a val, so n = n + 1 does not compile.
Expecting the program to fail only when it runs: the compiler checks every assignment first and reports 'val' cannot be reassigned., so nothing runs.