func_code_string: #include <bits/stdc++.h>   using namespace std;   string tolower(string str) {     for (int i = 0; i < str.size(); i++) str[i] = tolower(str[i]);     return str;   }   int main() {     int n;     cin >> n;     vector<string> store;     for (int i = 0; i < n; i++) {       string str;       cin >> str;       store.push_back(tolower(str));     }     string str, temp, ans =   ;     cin >> temp;     vector<int> color(temp.size());     str = tolower(temp);     char letter;     cin >> letter;     for (int i = 0; i < str.size(); i++) {       for (int j = 0; j < store.size(); j++) {         string& here = store[j];         if (i + here.size() <= str.size()) {           string substr = str.substr(i, here.size());           if (substr == here) {             for (int k = i; k < i + here.size(); k++) color[k] = 1;           }         }       }     }     char second = (letter ==  a ) ?  b  :  a ;     for (int i = 0; i < str.size(); i++) {       if (color[i])         ans += (str[i] == letter) ? second : letter;       else         ans += str[i];       if (isupper(temp[i])) ans[i] = toupper(ans[i]);     }     cout << ans << endl;     return 0;   }   