运行 ID: 91813

Main.cc: In function ‘std::__cxx11::string big_sqrt(std::__cxx11::string)’:
Main.cc:38:22: error: ‘add’ was not declared in this scope
         string sum = add(l, r);
                      ^~~
Main.cc:39:22: error: ‘div2’ was not declared in this scope
         string mid = div2(sum);
                      ^~~~
Main.cc:39:22: note: suggested alternative: ‘div’
         string mid = div2(sum);
                      ^~~~
                      div