Add all the A tasks

Task/Averages-Simple-moving-average/REXX/averages-simple-moving-average.rexx

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+/*REXX program is illustrate simple moving average. */
+arg p q n .                               /*get some arguments (maybe). */
+if p=='' then p=3                         /*the 1st period (default: 3).*/
+if q=='' then q=5                         /* "  2nd   "        "     5  */
+if n=='' then n=10                        /*number of items in the list.*/
+a.=0
+      do j=1 for n%2                      /*build beginning of the list,*/
+      a.j=j                               /* ... increasing values.     */
+      end   /*j*/
+
+                 do k=n%2 to 1 by -1      /* ... decreasing values.     */
+                 a.j=k
+                 j=j+1
+                 end   /*k*/
+
+                          do i=1 for n    /*show an indented item list. */
+                          say left('',60) 'item' right(i,3)'='right(a.i,3)
+                          end   /*i*/
+  do m=1 for n                            /*OK the, let's start the SMA.*/
+  smaP=sma(p,m)                           /*simple moving average for P.*/
+  smaQ=sma(q,m)                           /*  "      "       "     "  Q.*/
+
+                                          /*show 2 nicely formated SMAs.*/
+  say 'm='right(m,3),                     /*show where we're at in list.*/
+      "   sma("p')='left(sma(p,m),11),    /*show nicely aligned sma P.  */
+      "   sma("q')='left(sma(q,m),11)     /*  "    "       "     "  Q.  */
+  end   /*m*/
+exit
+/*────────────────────────────────────────SMA subroutine────────────────*/
+sma: procedure expose A.;   arg p,j;   s=0;   i=0
+              do k=max(1,j-p+1)   to j+p   for p   while k<=j
+              i=i+1
+              s=s+a.k
+              end
+return s/i