using System;

​

public class Calculator<T>

{

    private readonly Func<T, T, T> _func;

​

    public Calculator(Func<T, T, T> func)

    {

        _func = func;

    }

​

    public T Add(T c1, T c2)

    {

        return _func(c1, c2);

    }

}

public class Program

{

    public static void Main()

    {

        Func<int, int, int> intAddition = (a, b) => a + b;

        var intCalculator = new Calculator<int>(intAddition);

        Console.WriteLine(intCalculator.Add(1, 2)); // writes 3

​

​

        Func<string, string, string> stringAddition = (a, b) => a + b;

        var stringCalculator = new Calculator<string>(stringAddition);

        Console.WriteLine(stringCalculator.Add("Hello ", "world")); // writes "Hello world"

    }

}