View Compilation Error

0_0_39326182_3995.cpp: In function 'bool IsOk(std::string&)':
0_0_39326182_3995.cpp:35:33: error: use of an operand of type 'bool' in 'operator++' is forbidden in C++17
   35 |                                 vv++;
      |                                 ^~
0_0_39326182_3995.cpp: In function 'int main()':
0_0_39326182_3995.cpp:59:16: error: 'strcmp' was not declared in this scope
   59 |         while (strcmp(letter.c_str(),"end")) {
      |                ^~~~~~
0_0_39326182_3995.cpp:2:1: note: 'strcmp' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    1 | # include<iostream>
  +++ |+#include <cstring>
    2 | # include <string>