#include <stdio.h>
#include <string.h>
int main() {
  char orig[] = "abcdef";
  char tmp, *p, *q;
  int s;

  printf("orig: %s, orig = %p", orig, orig);
  for (p = orig; !*p; p++)
    printf("%c(%p)", *p, p);
  putchar('\n');
  
  s = strlen(orig);
  for (p = orig, q = orig + s - 1; p < q; p++, q--) {
    tmp = *p;
    *p = *q;
    *q = tmp;
  }

  printf("orig: %s, orig = %p", orig, orig);
  for (p = orig; !*p; p++)
    printf("%c(%p),", *p, p);
  putchar('\n');
  return 0;
}
/* end */

orig: abcdef, orig = 0xbfa3b4fd
orig: fedcba, orig = 0xbfa3b4fd