Initial data commit

Task/Forward-difference/Kotlin/forward-difference.kotlin

@@ -0,0 +1,36 @@
+// version 1.1.2
+
+fun forwardDifference(ia: IntArray, order: Int): IntArray {
+    if (order < 0) throw IllegalArgumentException("Order must be non-negative")
+    if (order == 0) return ia
+    val size = ia.size
+    if (size == 0) return ia  // same empty array
+    if (order >= size) return intArrayOf()  // new empty array
+    var old = ia
+    var new = old
+    var count = order
+    while (count-- >= 1) {
+       new = IntArray(old.size - 1)
+       for (i in 0 until new.size) new[i] = old[i + 1] - old[i]
+       old = new
+    }
+    return new
+}
+
+fun printArray(ia: IntArray) {
+    print("[")
+    for (i in 0 until ia.size) {
+        print("%5d".format(ia[i]))
+        if (i < ia .size - 1) print(", ")
+    }
+    println("]")
+}
+
+fun main(args: Array<String>) {
+    val ia = intArrayOf(90, 47, 58, 29, 22, 32, 55, 5, 55, 73)
+    for (order in 0..ia.size) {
+        val fd = forwardDifference(ia, order)
+        print("%2d".format(order) + ":  ")
+        printArray(fd)
+    }
+}