View Compilation Error

0_0_18166277_29515.cpp: In function 'int main()':
0_0_18166277_29515.cpp:106:20: error: invalid initialization of non-const reference of type 'std::string& {aka std::basic_string<char>&}' from an rvalue of type 'std::string {aka std::basic_string<char>}'
    insert(string(c));
                    ^
0_0_18166277_29515.cpp:42:6: note: in passing argument 1 of 'void insert(std::string&)'
 void insert(string &s)
      ^