update

Task/Optional-parameters/C/optional-parameters.c

@@ -20,8 +20,8 @@ struct {
 
 int CmprRows( const void *aa, const void *bb)
 {
-   String *rA = *(String **)aa;
-   String *rB = *(String **)bb;
+   String *rA = *(String *const *)aa;
+   String *rB = *(String *const *)bb;
    int sortCol = sortSpec.column;
 
    String left = sortSpec.reversed ? rB[sortCol] : rA[sortCol];
@@ -66,7 +66,7 @@ int sortTable(Table tbl, const char* argSpec,... )
          }
       }
    va_end(vl);
-   qsort( tbl->rows, tbl->n_rows, sizeof(String *), &CmprRows);
+   qsort( tbl->rows, tbl->n_rows, sizeof(String *), CmprRows);
    return 0;
 }
 

Task/Optional-parameters/REXX/optional-parameters-1.rexx

@@ -0,0 +1,19 @@
+sortStrings:  procedure expose @.      /*stemmed array is named:   @.   */
+col=1;    reverse='NO';    order='LEXICOGRAPHIC'     /*set the defaults.*/
+arg options
+               do j=1  for words(options);  x=word(options,j)
+
+                    select
+                    when datatype(x,'W')  then col=x/1
+                    when pos('=',x)==0    then order=x
+                    otherwise                  parse var x nam '=' value
+                    end   /*select*/
+               end        /*j*/
+
+              /*check for errors here:  COL isn't positive,             */
+              /*                        REVERSE value isn't NO or YES,  */
+              /*                        ORDER   value is recognized ... */
+
+... main body of string sort here ...
+
+return

Task/Optional-parameters/REXX/optional-parameters-2.rexx

@@ -0,0 +1,4 @@
+/*REXX example to use the  SortStrings  subroutine  with optional args. */
+                            /*...define array (@.nnn) of strings here...*/
+call sortStrings  'Reverse=no'  3
+                                       /*stick a fork in it, we're done.*/