Averages/Simple moving average: Difference between revisions

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 =={{header|D}}==
+<lang d>import std.stdio ;
-This should work properly for any types that act like numerics.
-<lang d>import std.stdio;
-import std.string;
+T delegate(T) Sma(T)(int period) {
-class MovingAvg(T) {
-        T[]elements;
+    T[] data = new T[](period);
-        int window = 5;
+    T drop, sum = cast(T) 0 ;
+    int index, filled, count ;
-        MovingAvg!(T) add(T input) {
-                elements ~= input;
-                return this;
+    foreach(ref e ; data) e = cast(T)0 ; // D initialize float type to NaN
-        }
-        void setWindow(int win) {window = win;}
+    T smaAcc(T v) {
-        T getAvg() {
+        drop = data[index] ;
-                if (!window) return 0;
+        data[index] = v ;
-                T sum = 0;
+        index = (index + 1) % period ;
+        sum += ( v - drop ) ;
-                int start = (elements.length-window<0?elements.length:elements.length-window);
-                if (start == elements.length) return 0;
+        if(filled >= period)
-                foreach(ele;elements[start..$]) {sum += ele;}
+            count = period ;
+        else
-                return sum/(elements.length-start);
-        }
+            count = ++filled ;
+        return sum / count;
+    }
+    return &smaAcc ;
 }
-int main() {
+void main() {
-        double[]nums = [1, 2, 3, 4, 5, 5, 4, 3, 2, 1];
-        auto mavg = new MovingAvg!(double);
+    auto s3 = Sma!(double)(3) ;
-        foreach(index,num;nums) {
+    auto s5 = Sma!(double)(5) ;
+    foreach(e ; [1, 2, 3, 4, 5, 5, 4, 3, 2, 1])
-                writefln("Average number %d is %s",index,toString(mavg.add(num).getAvg));
+        writefln("added %d , 3 period sma = %f , 5 period sma = %f", e, s3(e), s5(e)) ;
-        }
-        return 0;
 }</lang>