Anyone can know how to know this is leap year or not

Answer 1

if (year%400==0)
leap
else if (year%100==0)
not leap
else if (year%4==0)
leap
else
not leap

years multiple of 4 are leap BUT
those multiple of 100 (centuries) are not leap BUT
those multiple of 400 are again leap.

Answer 2

Hi
The year 2000 was a leap year . Also we can add 4 to a leap year to find the next one.So I think the years in Gregorian calendar which are divisible by 4 , are leap years.