func_code_string: #include <bits/stdc++.h>   int main() {     int n;     scanf( %d , &n);     char *str = new char[n + 1];     scanf( %s , str);     int size = strlen(str);     int sum1 = 0, sum2 = 0;     bool f = true;     for (int i = 0; i < size / 2; ++i) {       if ((str[i] ==  4  || str[i] ==  7 ) &&           (str[size - i - 1] ==  4  || str[size - i - 1] ==  7 )) {         sum1 += str[i] -  0 ;         sum2 += str[size - i - 1] -  0 ;       } else {         f = false;         break;       }     }     if (sum1 == sum2 && f)       printf( YES n );     else       printf( NO n );     return 0;   }   