func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxN = 1e5;   int n;   char ans[maxN + 1];   string s;   int main() {     ios_base::sync_with_stdio(false);     cin >> n;     cin.ignore();     for (int i = 0; i < n; i++) {       getline(cin, s);       for (int j = 0; j < s.length(); j++) {         if (ans[j] == 0) ans[j] =  ? ;         if (s[j] ==  ?  || ans[j] ==  X ) continue;         if (ans[j] ==  ?  && s[j] !=  ? )           ans[j] = s[j];         else if (ans[j] !=  ?  && s[j] !=  ?  && ans[j] != s[j])           ans[j] =  X ;       }     }     for (int i = 0; i < s.length(); i++) {       if (ans[i] ==  X )         ans[i] =  ? ;       else if (ans[i] ==  ? )         ans[i] =  a ;     }     cout << ans;     return 0;   }   