val tripleIt3: (Int) -> Int = { i: Int -> i * 3 } // Simplify things with it val quadItIt3: (Int) -> Int = { it * 4 } fun doubleIt3(i: Int): Int = i * 2 val doubleIt3: (Int) -> Int = ::doubleIt3 // Higher-order function as a parameter fun func3(i: Int, func: (Int) -> Int): Int = func.invoke(i) fun main() { println(func3(5, tripleIt3)) println(func3(10, quadItIt3)) println(func3(20, tripleIt3)) println(func3(30, ::doubleIt3)) println(func3(40, doubleIt3)) }