Initial data commit

Task/Exponentiation-operator/Elixir/exponentiation-operator.elixir

@@ -0,0 +1,31 @@
+defmodule My do
+  def exp(x,y) when is_integer(x) and is_integer(y) and y>=0 do
+    IO.write("int>   ")         # debug test
+    exp_int(x,y)
+  end
+  def exp(x,y) when is_integer(y) do
+    IO.write("float> ")         # debug test
+    exp_float(x,y)
+  end
+  def exp(x,y), do: (IO.write("       "); :math.pow(x,y))
+
+  defp exp_int(_,0), do: 1
+  defp exp_int(x,y), do: Enum.reduce(1..y, 1, fn _,acc -> x * acc end)
+
+  defp exp_float(_,y) when y==0, do: 1.0
+  defp exp_float(x,y) when y<0, do: 1/exp_float(x,-y)
+  defp exp_float(x,y), do: Enum.reduce(1..y, 1, fn _,acc -> x * acc end)
+end
+
+list = [{2,0}, {2,3}, {2,-2},
+        {2.0,0}, {2.0,3}, {2.0,-2},
+        {0.5,0}, {0.5,3}, {0.5,-2},
+        {-2,2}, {-2,3}, {-2.0,2}, {-2.0,3},
+        ]
+IO.puts "                    ___My.exp___  __:math.pow_"
+Enum.each(list, fn {x,y} ->
+  sxy = "#{x} ** #{y}"
+  sexp = inspect My.exp(x,y)
+  spow = inspect :math.pow(x,y)         # For the comparison
+  :io.fwrite("~10s = ~12s, ~12s~n", [sxy, sexp, spow])
+end)