
******
Listing 6

/* Write to printer, file, or nowhere using stdprn */

          if (where_to_go == GO_TO_PRINTER)
               file_printer = stdprn;
           else if (where_to_go == GO_TO_DISK_FILE)
               file_printer = fopen(filename, "w");
          else
               /* Dump to a Nul file */
               file_printer = fopen(NULL_DEVICE,"w");           

          /* print the line */ 
          fprintf (file_printer, "The answer is %10d", z);

          /* close the printer, if it is not the real printer */
          if (where_to_go != GO_TO_PRINTER)
             fclose (file_printer);

          }

*******

