ISBN号码

#include <iostream>
#include <string>
using namespace std;
int main() {    
string isbn;    
cin >> isbn;
    int sum = 0;    
int index = 1;        
for (int i = 0; i < isbn.length() - 1; i++) {        
if (isbn[i] != '-') {            
int num = isbn[i] - '0';            
sum += num * index;            
index++;
        }
    }        
// 计算正确的识别码    
int correctCode = sum % 11;    
char correctChar;    
if (correctCode == 10) {        
correctChar = 'X';
    } else {        
correctChar = correctCode + '0';
    }
    char inputCode = isbn[isbn.length() - 1];
    if (inputCode == correctChar) {        
cout << "Right" << endl;
    } else {        
isbn[isbn.length() - 1] = correctChar;        
cout << isbn << endl;
    }        
return 0;
}