September 2017 Update

Task/Digital-root-Multiplicative-digital-root/ALGOL-W/digital-root-multiplicative-digital-root.alg

@@ -0,0 +1,66 @@
+begin
+    % calculate the Multiplicative Digital Root (mdr) and Multiplicative Persistence (mp) of n %
+    procedure getMDR ( integer value  n
+                     ; integer result mdr, mp
+                     ) ;
+    begin
+        mp  := 0;
+        mdr := abs n;
+        while mdr > 9 do begin
+           integer v;
+           v   := mdr;
+           mdr := 1;
+           while begin
+               mdr := mdr * ( v rem 10 );
+               v   := v div 10;
+               v > 0
+           end do begin end;
+           mp := mp + 1;
+        end while_mdr_gt_9 ;
+    end getMDR ;
+
+    % task test cases %
+    write( "       N MDR MP" );
+    for n := 123321, 7739, 893, 899998 do begin
+        integer mdr, mp;
+        getMDR( n, mdr, mp );
+        write( s_w := 1, i_w := 8, n, i_w := 3, mdr, i_w := 2, mp )
+    end for_n ;
+
+    begin % find the first 5 numbers with each possible MDR %
+        integer requiredMdrs;
+        requiredMdrs := 5;
+        begin
+            integer array firstFew ( 0 :: 9, 1 :: requiredMdrs );
+            integer array mdrFOund ( 0 :: 9 );
+            integer       totalFound, requiredTotal, n;
+            for i := 0 until 9 do mdrFound( i ) := 0;
+            totalFound    := 0;
+            requiredTotal := 10 * requiredMdrs;
+            n             := -1;
+            while totalFound < requiredTotal do begin
+                integer mdr, mp;
+                n := n + 1;
+                getMDR( n, mdr, mp );
+                if mdrFound( mdr ) < requiredMdrs then begin
+                    % found another number with this MDR and haven't found enough yet %
+                    totalFound                       := totalFound + 1;
+                    mdrFound( mdr )                  := mdrFound( mdr ) + 1;
+                    firstFew( mdr, mdrFound( mdr ) ) := n
+                end if_found_another_MDR
+            end while_totalFound_lt_requiredTotal ;
+            % print the table of MDRs andnumbers %
+            write( "MDR: [n0..n4]" );
+            write( "===  ========" );
+            for v := 0 until 9 do begin
+                write( i_w := 3, s_w := 0, v, ": [" );
+                for foundPos := 1 until requiredMdrs do begin
+                    if foundPos > 1 then writeon( s_w := 0, ", " );
+                    writeon( i_w := 1, s_w := 0, firstFew( v, foundPos ) )
+                end for_foundPos ;
+                writeon( s_w := 0, "]" )
+            end for_v
+        end
+    end
+
+end.