View Compilation Error

0_0_39435482_26604.cpp: In function 'int main()':
0_0_39435482_26604.cpp:11:25: error: 'std::string' {aka 'class std::__cxx11::basic_string<char>'} has no member named 'strlen'
   11 |         for(int i=0;i<x.strlen();i++){
      |                         ^~~~~~
0_0_39435482_26604.cpp:12:20: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
   12 |             if(x[i]=="H"){
0_0_39435482_26604.cpp:15:25: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
   15 |             else if(x[i]=="O"){
0_0_39435482_26604.cpp:18:25: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
   18 |             else if(x[i]=="C"){