Initial data commit

Task/Forward-difference/D/forward-difference-2.d

@@ -0,0 +1,13 @@
+import std.stdio, std.algorithm, std.range, std.array;
+
+auto forwardDifference(Range)(Range d, in int level) pure {
+    foreach (immutable _; 0 .. level)
+        d = d.zip(d.dropOne).map!(a => a[0] - a[1]).array;
+    return d;
+}
+
+void main() {
+    const data = [90.5, 47, 58, 29, 22, 32, 55, 5, 55, 73.5];
+    foreach (immutable level; 0 .. data.length)
+        forwardDifference(data, level).writeln;
+}