else if (this->s_value == "++"){
            result = c_children[0]->getResult(i_variables_values, sp_variables, i_variable_length) + c_children[1]->getResult(i_variables_values, sp_variables, i_variable_length) + c_children[2]->getResult(i_variables_values, sp_variables, i_variable_length);
        }