update

Task/Averages-Simple-moving-average/Objeck/averages-simple-moving-average.objeck

@@ -0,0 +1,45 @@
+use Collection;
+
+class MovingAverage {
+  @window : FloatQueue;
+  @period : Int;
+  @sum : Float;
+
+  New(period : Int) {
+    @window := FloatQueue->New();
+    @period := period;
+  }
+
+  method : NewNum(num : Float) ~ Nil {
+    @sum += num;
+    @window->Add(num);
+    if(@window->Size() > @period) {
+      @sum -= @window->Remove();
+    };
+  }
+
+  method : GetAvg() ~ Float {
+    if(@window->IsEmpty()) {
+      return 0; # technically the average is undefined
+    };
+
+    return @sum / @window->Size();
+  }
+
+  function : Main(args : String[]) ~ Nil {
+    testData := [1.0, 2.0, 3.0, 4.0, 5.0, 5.0, 4.0, 3.0, 2.0, 1.0];
+    windowSizes := [3.0, 5.0];
+
+    each(i : windowSizes) {
+      windSize := windowSizes[i];
+      ma := MovingAverage->New(windSize);
+      each(j : testData) {
+        x := testData[j];
+        ma->NewNum(x);
+        avg := ma->GetAvg();
+        "Next number = {$x}, SMA = {$avg}"->PrintLine();
+      };
+      IO.Console->PrintLine();
+    };
+  }
+}

Task/Averages-Simple-moving-average/Racket/averages-simple-moving-average.rkt

@@ -0,0 +1,21 @@
+#lang racket
+
+(require data/queue)
+
+(define (simple-moving-average period)
+  (define queue (make-queue))
+  (define sum 0.0)
+
+  (lambda (x)
+    (enqueue! queue x)
+    (set! sum (+ sum x))
+    (when (> (queue-length queue) period)
+      (set! sum (- sum (dequeue! queue))))
+    (/ sum (queue-length queue))))
+
+;; Tests
+(define sma3 (simple-moving-average 3))
+(define sma5 (simple-moving-average 5))
+(for/lists (lst1 lst2)
+           ([i '(1 2 3 4 5 5 4 3 2 1)])
+  (values (sma3 i) (sma5 i)))