JuniorTheoryCommon

What happens when you build and run this program?

KOTLIN

fun main() {
    val small: Int = 5
    val big: Long = small
    println(big)
}

It does not compile: an Int does not turn into a Long by itself

Expecting 5: a Long variable accepts only a Long, and Kotlin never converts an Int for you; write val big: Long = small.toLong().
Expecting a run-time failure: types are checked while building, so the compiler reports initializer type mismatch and nothing runs.

JuniorTheoryCommon

KOTLIN

fun main() {
    val small: Int = 5
    val big: Long = small
    println(big)
}

It does not compile: an Int does not turn into a Long by itself

Expecting 5: a Long variable accepts only a Long, and Kotlin never converts an Int for you; write val big: Long = small.toLong().
Expecting a run-time failure: types are checked while building, so the compiler reports initializer type mismatch and nothing runs.