langs a-z

Task/Averages-Arithmetic-mean/Standard-ML/averages-arithmetic-mean-1.ml

@@ -0,0 +1,4 @@
+fun mean_reals [] = 0.0
+  | mean_reals xs = foldl op+ 0.0 xs / real (length xs);
+
+val mean_ints = mean_reals o (map real);

Task/Averages-Arithmetic-mean/Standard-ML/averages-arithmetic-mean-2.ml

@@ -0,0 +1,20 @@
+fun mean_reals [] = raise Empty
+  | mean_reals xs = let
+    val (total, length) =
+      foldl
+        (fn (x, (tot,len)) => (x + tot, len + 1.0))
+        (0.0, 0.0) xs
+    in
+      (total / length)
+    end;
+
+
+fun mean_ints [] = raise Empty
+  | mean_ints xs = let
+    val (total, length) =
+      foldl
+        (fn (x, (tot,len)) => (x + tot, len + 1.0))
+        (0, 0.0) xs
+    in
+      (real total / length)
+    end;