Add all the A tasks

Task/Averages-Simple-moving-average/Go/averages-simple-moving-average.go

@@ -0,0 +1,34 @@
+package main
+
+import "fmt"
+
+func sma(n int) func(float64) float64 {
+    s := make([]float64, 0, n)
+    i, sum, rn := 0, 0., 1/float64(n)
+    return func(x float64) float64 {
+        if len(s) < n {
+            sum += x
+            s = append(s, x)
+            return sum / float64(len(s))
+        }
+        s[i] = x
+        i++
+        if i == n {
+            i = 0
+        }
+        sum = 0
+        for _, x = range s {
+            sum += x
+        }
+        return sum * rn
+    }
+}
+
+func main() {
+    sma3 := sma(3)
+    sma5 := sma(5)
+    fmt.Println("x       sma3   sma5")
+    for _, x := range []float64{1, 2, 3, 4, 5, 5, 4, 3, 2, 1} {
+        fmt.Printf("%5.3f  %5.3f  %5.3f\n", x, sma3(x), sma5(x))
+    }
+}