#include <stdio.h>
/* Define doubling_time first */   /**/
double doubling_time (double r) {  /**/
  return 72.0 / r;                 /**/
}                                  /**/
main ( ) {
  double r = 5.0;
  printf ("Your money doubles in about %f years at %f percent.\n",
                                       doubling_time (4.0),
                                                   4.0);
  printf ("Your money doubles in about %f years at %f percent.\n",
                                       doubling_time (r),
                                                   r);
  printf ("Your money doubles in about %f years at %f percent.\n",
                                       doubling_time (r + 1.0),
                                                   r + 1.0);
}