Initial data commit

Task/Ackermann-function/REXX/ackermann-function-2.rexx

@@ -0,0 +1,21 @@
+/*REXX program  calculates and displays  some values for the  Ackermann function.       */
+high=24
+         do     j=0  to 3;                    say
+             do k=0  to high % (max(1, j))
+             call tell_Ack  j, k
+             end   /*k*/
+         end       /*j*/
+exit                                             /*stick a fork in it,  we're all done. */
+/*──────────────────────────────────────────────────────────────────────────────────────*/
+tell_Ack:  parse arg mm,nn;   calls=0            /*display an echo message to terminal. */
+           #=right(nn,length(high))
+           say 'Ackermann('mm", "#')='right(ackermann(mm, nn), high),
+                                      left('', 12)     'calls='right(calls, high)
+           return
+/*──────────────────────────────────────────────────────────────────────────────────────*/
+ackermann: procedure expose calls                /*compute value of Ackermann function. */
+           parse arg m,n;   calls=calls+1
+           if m==0  then return n + 1
+           if n==0  then return ackermann(m-1, 1)
+           if m==2  then return n + 3 + n
+                         return ackermann(m-1, ackermann(m, n-1) )