a.c

a.c

#include <stdio.h>
#define GOOD1  99586915107664152904966939075856564224.0
#define GOOD2 298759386401549014052982412761733529600.0
#define BAD   298759406683958617704652836708984815616.0

int isGood(float x) {
  return 1.0 / (1.0 / x) == x;
}

float disc(float x) {
  return 1.0 / (1.0 / x) - x;
}

int main() {
  printf("%d\n", isGood(GOOD1));
  printf("%d\n", isGood(GOOD2));
  printf("%d\n", isGood(BAD));
  printf("%f\n", disc(BAD));
}