C++中stoi函数显示参数无效该怎样修改

C++中stoi函数显示参数无效该怎样修改

else {
        int result;
         
        try {
           result=stoi(root->value);
        }
        catch (std::invalid_argument&) {
            // if no conversion could be performed
            cout << "Invalid_argument" << endl;
        }
        catch (std::out_of_range&) {
            // if the converted value would fall out of the range of the result type 
            // or if the underlying function (std::strtol or std::strtoull) sets errno 
            // to ERANGE.
            cout << "Out of range" << endl;
        }
        catch (...) {
            // everything else
            cout << "Something else" << endl;
        }
        return result;
    }