class Program {

        delegate T BinaryOperator<T>(T opA, T opB);

        static int Add(int a, int b) {
            return a + b;
        }
        static int Subtract(int a, int b) {
            return a - b;
        }

        static void Main(string[] args) {

            BinaryOperator<int>[] operators = new BinaryOperator<int>[2];
            operators[0] = Add;
            operators[1] = Subtract;

            Console.WriteLine(operators[0](2, 4));
            Console.WriteLine(operators[1](3, 5));
        }
    }