我得到了以下代码:(代码现场:C++ Shell)
class Worker
{
public:
Worker (std::string name):_name (name) {};
Worker (const Worker & worker):_name (worker._name)
{ std::cout << _name << " got copied!" << std::endl; }
Worker (Worker && other):_name (other._name)
{ std::cout << _name << " got moved!" << std::endl; }
~Worker ()
{ std::cout << _name << " got destroyed!" << std::endl; }
void changeName(std::string name)
{ this->_name = name; }
private:
std::string _name;
};
class Factory
{
public:
Factory ()
{ std::cout << "Factory got created!" << std::endl; }
~Factory ()
{ std::cout << "Factory got destroyed!" << std::endl; }
void addWorker (Worker & worker)
{ this->workers.push_back (std::move (worker)); }
Worker & getLastWorker ()
{ this->workers.back (); }
private:
std::vector < Worker > workers;
};
int main ()
{
auto factory = std::make_unique < Factory > ();
Worker w1 ("Bob");
factory->addWorker (w1);
Worker & workerRef = factory->getLastWorker ();
//workerRef.changeName("Mary");
return 0;
}
我有一个 Factory
,它将其 Workers
存储在一个向量中。当我运行 main()
时,我会得到以下输出:
Factory got created!
Bob got moved!
Bob got destroyed!
Factory got destroyed!
Bob got destroyed!
我无法理解为什么 Bob got destroyed!
出现了两次,因为我认为 Worker w1
在 Factory
中被移动到向量 workers
中。此外,如果您将 workerRef.changeName("Mary");
注释掉,代码会崩溃,并显示 Segmentation fault
。
我已经使用 C++ 编程一个月了,但在这里真的很困难。我已经查找了一段时间,但找不到线索,所以任何帮助都是好的!