DateTime.IsLeapYear() Method in C#

This method returns an indication of whether the specified year is a leap year or not. Here, the year is always interpreted as a year in the Gregorian calendar.

Syntax:

public static bool IsLeapYear (int year);

Return Value: This method return true if year is a leap year otherwise it returns false.

Exception: This method will give ArgumentOutOfRangeException if the year is less than 1 or greater than 9999.

Below programs illustrate the use of above-discussed method:

Example 1:

C#

// C# code to demonstrate the
// IsLeapYear(Int32) Method
using System;

class GFG {

    // Main Method
    public static void Main()
    {

        // Checking the leap year between 2000 to 2019
        for (int y = 2000; y <= 2019; y++)
        {

            // using method
            if (DateTime.IsLeapYear(y))
            {
                Console.WriteLine("{0} is a Leap Year.", y);
            }

            else
            {
                Console.WriteLine("{0} is not a Leap Year.", y);
            }
        }
    }
}

Output:

2000 is a Leap Year.
2001 is not a Leap Year.
2002 is not a Leap Year.
2003 is not a Leap Year.
2004 is a Leap Year.
2005 is not a Leap Year.
2006 is not a Leap Year.
2007 is not a Leap Year.
2008 is a Leap Year.
2009 is not a Leap Year.
2010 is not a Leap Year.
2011 is not a Leap Year.
2012 is a Leap Year.
2013 is not a Leap Year.
2014 is not a Leap Year.
2015 is not a Leap Year.
2016 is a Leap Year.
2017 is not a Leap Year.
2018 is not a Leap Year.
2019 is not a Leap Year.

Example 2:

C#

// C# code to demonstrate the
// IsLeapYear(Int32) Method
using System;

class GFG {

    // Main Method
    public static void Main()
    {

        // using method
        if (DateTime.IsLeapYear(9999))
        {
            Console.WriteLine("9999 is a Leap Year.");
        }

        else
        {
            Console.WriteLine("9999 is not a Leap Year.");
        }

        // using method will give an error
        // as year's value is greater than
        // 9999
        if (DateTime.IsLeapYear(10000))
        {
            Console.WriteLine(" 10000 is a Leap Year.");
        }

        else {
            Console.WriteLine("10000 is not a Leap Year.");
        }
    }
}

Runtime Error:

Unhandled Exception: 
System.ArgumentOutOfRangeException: Year must be between 1 and 9999. 
Parameter name: year 

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.datetime.isleapyear?view=netframework-4.7.2