Initial data commit

Task/Forward-difference/D/forward-difference-1.d

@@ -0,0 +1,19 @@
+T[] forwardDifference(T)(in T[] data, in int level) pure nothrow
+in {
+    assert(level >= 0 && level < data.length);
+} body {
+    auto result = data.dup;
+    foreach (immutable i; 0 .. level)
+        foreach (immutable j, ref el; result[0 .. $ - i - 1])
+            el = result[j + 1] - el;
+    result.length -= level;
+    return result;
+}
+
+void main() {
+    import std.stdio;
+
+    const data = [90.5, 47, 58, 29, 22, 32, 55, 5, 55, 73.5];
+    foreach (immutable level; 0 .. data.length)
+        forwardDifference(data, level).writeln;
+}