Control Flow If Expression In Kotlin, if is an expression, i.e. it returns a value. Therefore there is no ternary operator (condition ? then : else), because ordinary if works fine in this role. // Traditional usage var max = a if (a < b) max = b // With else var max: Int if (a > b) { max = a } else { max = b } // As expression val max = if (a > b) a else b if branches can be blocks, and the last expression is the value of a block: val max = if (a > b) { print("Choose a") a } else { print("Choose b") b } If you're using if as an expression rather than a statement (for example, returning its value or assigning it to a variable), the expression is required to have an else branch. When Expression when replaces the switch operator of C-like languages. In the simplest form it looks like this when (x) { 1 -> print("x == 1") 2 -> print("x == 2") else -> { // Note the...