gp_demo.kt

/**
 *@author mhashim6 on 31/10/2019
 */

fun main() {

    val ns = arrayOf(5, 6, 7)
    val p1 = Point(5, 7)
    val p2 = Point(5, 6)

    val ps = arrayOf(p1, p2)
    println(sum(ns) { x1, x2 -> (x1 ?: 0) + (x2 ?: 0) })
    println(sum(ps) { point1, point2 ->
        Point(
            (point1?.x ?: 0) + (point2?.x ?: 0),
            (point1?.y ?: 0) + (point2?.y ?: 0)
        )
    })
}

fun <T> sum(ns: Array<T>, algorithm: (T?, T?) -> T): T? {
    var res: T? = null
    for (n in ns)
        res = algorithm(n, res)
    return res

}

data class Point(var x: Int, var y: Int)


fun Point.square() = Point(x * x, y * y)