C

int compare_doubles (const double *a, const double *b) {  double temp = *a - *b;  if (temp > 0)  return 1;  else if (temp < 0)  return -1;  else  return 0; } main() {  double *array;  int size;  ...  qsort (array, size, sizeof (double), compare_doubles); } 

#define COMMAND(NAME) { #NAME, NAME ## _command }   struct command commands[] = {  COMMAND (quit),  COMMAND (help),  ... };