c++ - "binary '[' : no operator found -

i have 2 vectors of strings:

std::vector<std::string> savestring{"1", "3", "2", "4"}; // numbers std::vector<std::string> save2{"a", "b", "c", "d"};      // names 

and wish reorder latter based on former, ends being {"a", "c", "b", "d"}. tried this:

for (int i=0; i<savestring.size(); i++) {     savestring[i] = save2[savestring[i]]; } 

but getting error:

"binary '[' : no operator found takes right-hand operand of type 'std::basic_string<_elem,_traits,_alloc>' (or there no acceptable conversion)"

what mean , wrong code?

the problem savestring[i] std::string whereas there should integer inside square brackets in save2[]. so, solution first convert std::string integer writing custom function.

so, change to:

// converts std::string int int toint( const std::string& obj ) {     std::stringstream ss;     ss << obj;      int ret;     ss >> ret;      return ret; }   for(int i=0;i<savestring.size();i++) {     savestring[i]=save2[toint(savestring[i])]; } 

don't forget include sstream header writing #include <sstream> @ top.