C++ İle Market Otomasyonu Programı [efeede]

#include <iostream>
using namespace std;
int main(){
	int sec;
	string type, num, guv;
int sum = 0, i;
cout << "Kartiniz Visa Kartmi Master Cardmi?"<<endl;
cin >> type;
cout << "Lutfen 16 Haneli Kart Numaranizi Giriniz" << endl;
cin>>num;
cout << "Lutfen Kartinizin Güvenlik Kodunu Giriniz" << endl;
cin>>guv;
for(int a = 0; a < 3; a++)
{
sum += (guv[a] - 9);
}
sum %= 10;
  if(sum == 0,1 && guv.size() == 3) {
///////////////////////////////////////////////////////////////////////////////////////////////////////////
for(i = 0; i < 16; i++)
{
sum += (num[i] - 48);
}
sum %= 10;
  if(sum == 0,1 && num.size() == 16) { 
  cout << "Bu Gecerli Bir Kart" << endl;
	cout << "Lutfen Asagidakilerden Istediginiz Secenegin Numarasini Yaziniz" <<endl;
	cout << "1-Ulker Cikolatali Gofret 1TL" << endl; 
	cout << "2-Browni Cikolata 1TL" << endl; 
	cout << "3-LAYS Sade Cips 2TL" << endl; 
	cout << "4-Coca Cola 330ML Icecek 2TL" << endl;
	cout << "Seciminizin Numarasini Yaziniz" << endl; 
	cin >> sec;
	if(sec == 1){
		cout << "Ulker Cikolatali Gofret 1TL Kartinizdan Cekilmistir" << endl;
	}
	if(sec == 2){
		cout << "Browni Cikolata 1TL Kartinizdan Cekilmistir" << endl;
	}
	if(sec == 3){
		cout << "LAYS Sade Cips 2TL Kartinizdan Cekilmistir" << endl;
	}
	if(sec == 4){
		cout << "Coca Cola 330ML Icecek 2TL Kartinizdan Cekilmistir" << endl;
	}
}
}
    system("pause");
}