using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

​

namespace IDataTypeeeeeeeeeee

{

    public interface IDataType

    {

        object Add(object other); 

        void SetVal(object other);

    }

    public interface IDataType<T> where T : IDataType, new()

    {

        T Add(T other);

    }

    class IntegerDataType : IDataType

    {

        public int Data { get; set; }

​

        public object Add(object other)

        {

            int o = ((IntegerDataType)other).Data;

            return Data + o;

        }

        public void SetVal(object other)

        {

            Data = (int)other;

        }

    }

​

    class DoubleDataType : IDataType

    {

        public double Data { get; set; }

​

        public object Add(object other)

        {

            double o = ((DoubleDataType)other).Data;

            return Data + o;

        }

​

        public void SetVal(object other)

        {

            Data = (double)other;

        }

    }

​

    public class DataType<T> : IDataType<T> where T : IDataType, new()//https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/new-constraint

    {

        IDataType _item;

        public DataType(IDataType item)

        {

            _item = item;

        }

​

        public T Add(T other)

        {

            object o = _item.Add(other);

​

            T t = new T();

​

            t.SetVal(o);

​

            return t;

        }

    }

​

    public class MainClass

    {

        public static void Main(string[] args)

        {

            //IntegerDataType item1 = new IntegerDataType();

            //item1.Data = 10;

​

            //IntegerDataType item2 = new IntegerDataType();

            //item2.Data = 20;

​

            //DataType<IntegerDataType> l1 = new DataType<IntegerDataType>(item1);

            //IntegerDataType sum1 = l1.Add(item2);

​

            DoubleDataType item3 = new DoubleDataType();

            item3.Data = 10.5;

​

            DoubleDataType item4 = new DoubleDataType();

            item4.Data = 20.5;

​

            DataType<DoubleDataType> l2 = new DataType<DoubleDataType>(item3);

            DoubleDataType sum2 = l2.Add(item4);

        }

    }

}

​