Initial data commit

Task/Stack/Eiffel/stack.e

@@ -0,0 +1,43 @@
+class
+	STACK_ON_ARRAY
+
+create
+	make
+
+feature -- Implementation
+
+	empty: BOOLEAN
+		do
+			Result := stack.is_empty
+		ensure
+			empty: Result = (stack.count = 0)
+		end
+
+	push (item: ANY)
+		do
+			stack.force (item, stack.count)
+		ensure
+			pushed: stack [stack.upper] = item
+			growth: stack.count = old stack.count + 1
+		end
+
+	pop: ANY
+		require
+			not_empty: not empty
+		do
+			Result := stack.at (stack.upper)
+			stack.remove_tail (1)
+		ensure
+			reduction: stack.count = old stack.count - 1
+		end
+
+feature {NONE} -- Initialization
+
+	stack: ARRAY [ANY]
+
+	make
+		do
+			create stack.make_empty
+		end
+
+end