うるう年かどうかを判断する方法を作成します.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace  _ _
{
    class Program
    {    
        /// <summary>
        ///  
        /// </summary>
        /// <param name="year"> </param>
        /// <returns> </returns>
        public static bool IsRun(int year)
        {
            bool b = (year % 400 == 0) || (year % 4 == 0 && year % 100 != 0);
            return b;
        }
        static void Main(string[] args)
        {
            bool b = IsRun(int.Parse(Console.ReadLine()));
            Console.WriteLine(b);
            Console.ReadLine();
            
        }
    }
}