Sicily 1129. ISBN

 1 #include <iostream>
 2 #include <string>
 3 using namespace std;
 4 
 5 int Sum(string x) {
 6     int sum = 0;
 7     int weight = 10;
 8     for (int i = 0; i < x.size(); i++) {
 9         if (x[i] >= ‘0‘&&x[i] <= ‘9‘) {
10             sum += (x[i]-‘0‘)*(weight--);
11         }
12     }
13     return sum;
14 }
15 
16 int main() {
17     string test;
18     while (cin >> test) {
19         int sum = Sum(test);
20         int check_digit = sum%11 == 0 ? 0 : 11-sum%11;
21         check_digit == 10 ? cout << test << "-X\n"
22             : cout << test << "-" << check_digit << endl;
23     }
24     
25     return 0;
26 }