new files

Task/Entropy/Ada/entropy.ada

@@ -0,0 +1,28 @@
+with Ada.Text_IO, Ada.Float_Text_IO, Ada.Numerics.Elementary_Functions;
+
+procedure Count_Entropy is
+
+   package TIO renames Ada.Text_IO;
+
+   Count: array(Character) of Natural := (others => 0);
+   Sum:   Natural := 0;
+   Line: String := "1223334444";
+
+begin
+   for I in Line'Range loop   -- count the characters
+      Count(Line(I)) := Count(Line(I))+1;
+      Sum := Sum + 1;
+   end loop;
+
+   declare   -- compute the entropy and print it
+      function P(C: Character) return Float is (Float(Count(C)) / Float(Sum));
+      use Ada.Numerics.Elementary_Functions, Ada.Float_Text_IO;
+      Result: Float := 0.0;
+   begin
+      for Ch in Character loop
+         Result := Result -
+          (if P(Ch)=0.0 then 0.0 else P(Ch) * Log(P(Ch), Base => 2.0));
+      end loop;
+      Put(Result, Fore => 1, Aft => 5, Exp => 0);
+   end;
+end Count_Entropy;