Leap Year

#include <stdio.h>
#include <stdbool.h>
bool isLeapYear(int year) {
  if (year < 1582) return false;
  return ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0));
}
int main(void) {
  int i, years[] = {2000, 2001, 2002, 2003, 2004, 2005, 2100, 2200, 2300, 2400};
  for (i = 0; i < (int) sizeof(years) / sizeof(int); i++) {
    printf("%d is %s.\n", years[i],
      (isLeapYear(years[i]) ? "leap year" : "not leap year"));
  }
  return 0;
}