static void Main(string[] args)
{
congthuctoan ct = new congthuctoan(tong);
congthuctoan ct2 = new congthuctoan(hieu);
congthuctoan ct3 = new congthuctoan(tich);
congthuctoan tonghop;
tonghop = ct + ct2 + ct3;
//Console.Write("{0}", tonghop(1, 2));
Console.Write("{0}", ctt(1, 2, tong));
Console.ReadKey();
}
static int ctt(int a, int b, congthuctoan ct)
{
return(ct(a, b));
}
