MostafaNasiri

interface Processor<T> {
    fun process(): T
}

class ExampleProcessor : Processor<Unit> {
    override fun process() {
        // Do something
    }
}

MostafaNasiri

fun main() {
    val anInt = 2
    val aLong: Long = anInt // Error: Type mismatch
    aLong = anInt.toLong() // This is correct

    val stringNum = "123"
    val num = stringNum.toInt()
}

MostafaNasiri

fun main() {
    var city: String = "New York"

    // You can omit the type if you declare and initialize a variable at the same time
    var city = "New York"

    // But you can't do something like this:
    var city // Error: Either specify the variable type or initialize it
    city = "New York"