ISBN不会写 大佬们请原谅我才学C++不到三个月 但是AC不了 求大佬帮助

#include<bits/stdc++.h>
using namespace std;
int digit[9];
int main()
{
    int i,s,b,n,sum,r,bi,bs,bb,bn;
    char g1,g2,g3;
    cin >> i >> g1 >> s >> g2 >> b >> g3 >> n ;
    bi = i;
    bs = s;
    bb = b;
    bn = n;
    digit[1]=i;
    for (int x=2;x<=4;x++){
        digit[x]=s%10;
        s/=10;
    }    
    for (int j=5;j<=9;j++){
        digit[j]=b%10;
        b/=10;
    }    
    for (int u=1;u<=9;u++){
        digit[u]=digit[u]*u;
        sum+=digit[u];
    }
    r = sum%11;
    if(n==r){
        cout << "Right";
    }
    else{
        cout << bi << g1 << bs << g2 << bb << g3 << r ;
    }    
    return 0;
}

求救