t.c

#include <stdio.h>

typedef struct {
  double t;
} temp;

int main() {
  temp a, b;
  a.t = 999999999999999999;
  b.t = 1000000000000000000;
  for (size_t i = 0; i < sizeof(double); ++i) {
    printf("%4d - %4d\n", *((char *)&a + i), *((char *)&b + i));
  }
  return 0;
}