Song.cs

//program.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static double Memuza(Song song1, Song song2)
        {
            return (double)(song1.GetLength() + song2.GetLength()) / 2;
        }

        static void Main(string[] args)
        {
            Song song1 = new Song(int.Parse(Console.ReadLine()), int.Parse(Console.ReadLine()));
            Song song2 = new Song(int.Parse(Console.ReadLine()), int.Parse(Console.ReadLine()));
            Console.WriteLine(Memuza(song1, song2));
            song2.SetLength(song1.GetLength()/2);
            Console.WriteLine(Memuza(song1, song2));
        }
    }
}
//song.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Song
    {
        private int length, siduri;

        public Song(int length, int siduri)
        {
            this.length = length;
            this.siduri = siduri;
        }

        public int GetLength()
        {
            return this.length;
        }

        public int GetSiduri()
        {
            return this.siduri;
        }

        public void SetLength(int length)
        {
            this.length = length;
        }

        public void SetSiduri(int siduri)
        {
            this.siduri = siduri;
        }

        public string ToString()
        {
            return "length is " + this.length + ", siduri is " + this.siduri;
        }
    }
}