A-M baby

Task/Gray-code/REXX/gray-code.rexx

@@ -0,0 +1,25 @@
+/*REXX program to convert decimal───> binary ───> gray code ───> binary.*/
+parse arg N .;    if N=='' then N=31   /*Not specified? Then use default*/
+L=max(1,length(strip(x2b(d2x(N)),'L',0)))   /*for cell width formatting.*/
+w=14                                   /*used for cell width formatting.*/
+_=center('binary',w,'─')               /*2nd and 4th part of the header.*/
+say center('decimal',w,'─')">" _">" center('gray code',w,'─')">" _ /*hdr*/
+
+     do j=0  to N;     b=right(x2b(d2x(j)),L,0)      /*handle 0  ──►  N.*/
+     g=b2gray(b)                       /*convert binary to gray code.   */
+     a=gray2b(g)                       /*convert gray code to binary.   */
+     say center(j,w+1) center(b,w+1) center(g,w+1) center(a,w+1)  /*tell*/
+     end   /*j*/
+exit                                   /*stick a fork in it, we're done.*/
+/*───────────────────────────────────B2GRAY subroutine──────────────────*/
+b2gray: procedure; parse arg x
+$=left(x,1);                    do b=2  to length(x)
+                                $=$||(substr(x,b-1,1) && substr(x,b,1))
+                                end   /*b*/        /* && is eXclusive OR*/
+return $
+/*───────────────────────────────────GRAY2B subroutine──────────────────*/
+gray2b: procedure; parse arg x
+$=left(x,1);                    do g=2  to length(x)
+                                $=$ || (right($,1)    && substr(x,g,1))
+                                end   /*g*/        /* && is eXclusive OR*/
+return $