func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     string s;     int n, m, len;     cin >> n >> m;     if (n >= 1 && n <= 100 && m >= 1 && m <= 100) {       cin >> s;       len = s.size();       if (len == n) {         int l, r, z;         char c1, c2;         while (m--) {           cin >> l >> r >> c1 >> c2;           if (l >= 1 && l <= r && r <= n && c1 >=  a  && c1 <=  z  && c2 >=  a  &&               c2 <=  z )             for (z = l - 1; z <= r - 1; z++) {               if (s[z] == c1) {                 s[z] = c2;               }             }         }         cout << s << endl;       }     }   }   