Is it a leap year
A billing schedule needs to know whether February has 29 days.
- A year divisible by 4 is a leap year, except that a year divisible by 100 is not, unless it is also divisible by 400.
- Anything below year 1 is not a year at all.
IsLeapYear(year: int) → bool
C# needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
public bool IsLeapYear(int year) {
}Worked examples
| Call | Result |
|---|---|
IsLeapYear(2024) | true |
IsLeapYear(2023) | false |
IsLeapYear(1900) | false |
IsLeapYear(2000) | true |
Hint
The 400 rule wins over the 100 rule, which wins over the 4 rule. Order the checks accordingly.
Reference solution in C#
public bool IsLeapYear(int year) {
if (year < 1) return false;
if (year % 400 == 0) return true;
if (year % 100 == 0) return false;
return year % 4 == 0;
}