Data commit

Task/Ackermann-function/Eiffel/ackermann-function.e

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+class
+	ACKERMAN_EXAMPLE
+
+feature -- Basic Operations
+
+	ackerman (m, n: NATURAL): NATURAL
+			-- Recursively compute the n-th term of a series.
+		require
+			non_negative_m: m >= 0
+			non_negative_n: n >= 0
+		do
+			if m = 0 then
+				Result := n + 1
+			elseif m > 0 and n = 0 then
+				Result := ackerman (m - 1, 1)
+			elseif m > 0 and n > 0 then
+				Result := ackerman (m - 1, ackerman (m, n - 1))
+			else
+				check invalid_arg_state: False end
+			end
+		end
+
+end