#include<stdio.h>
#include<unistd.h>

#include<sys/types.h>
#include<sys/stat.h>

int main(int argc, char * argv[]) {

   int ch ;
   int a_certain_number;

   while ( (ch=getopt(argc,argv,"abcd:e"))!=-1 ) {
      printf("%c", ch ) ;
      if ( ch=='d' ) printf(" %s", optarg ) ;
      printf("\n") ;
   }

   printf("bye.\n") ;
   printf("But before we go...\n") ;

   a_certain_number = -1  ;
   printf("%x %x\n", S_IFDIR,  S_IFDIR & a_certain_number ) ;
}