FUNCTION c_isleap(year)
long *year;
The year to be tested. The year may be a two-digit year, implying 1900+year (e.g., 84 which implies 1984) or a four-digit year (e.g., 1984).
The function returns TRUE if year is a leap year, and FALSE otherwise. A year is a leap year if it is divisible by 4, with the following exceptions: Years divisible by 100 are NOT leap years, but years divisible by 400 ARE leap years.
c_isleap() returns
TRUE (1) --> The year is a leap year. FALSE (0) --> The year is not a leap year.