c++11 thread 初始化

class background_task{
public:
    int id;
    int value;
    background_task(int _id, int _value):id(_id),value(_value){
        output();
        std::cout << "initialize.\n";
    }
    void do_something(){
        std::cout << "id = " << id << std::endl;
        id = 2;
        std::cout << "do something.\n";
        std::cout << "id = " << id << std::endl;
    }

    void do_something_else(){
        std::cout << "value = " << value << std::endl;
        value = 20;
        std::cout << "do something else.\n";
        std::cout << "value = " << value << std::endl;
    }

    void output(){
        std::cout << "ID = " << id << ", value = " << value << std::endl;
    }

   // void operator() (background_task &){
    void operator() (){

        do_something();
        do_something_else();
    }

};





int main()
{

    background_task tf(1,10);
    tf.output();
    std::thread t(tf);
    
    //tf.do_something();
    //tf.do_something_else();

    tf.output();
    t.join();
    tf.output();
}