问题描述
我有这门课
class CamFeed {
public:
// constructor
CamFeed(ofVideoGrabber &cam);
ofVideoGrabber &cam;
};
还有这个构造函数:
CamFeed::CamFeed(ofVideoGrabber &cam) {
this->cam = cam;
}
我在构造函数上收到此错误:'' 的构造函数必须显式初始化引用成员 ''
I get this error on the constructor: Constructor for '' must explicitly initialize the reference member ''
有什么好的方法可以解决这个问题?
What is a good way to get around this?
推荐答案
需要使用构造函数初始化列表:
You need to use the constructor initializer list:
CamFeed::CamFeed(ofVideoGrabber& cam) : cam(cam) {}
这是因为引用必须引用某些东西,因此不能默认构造.进入构造函数体后,所有数据成员都已初始化.您的 this->cam = cam;
行实际上是一个赋值,将 cam
引用的值分配给任何 this->cam
> 指的是.
This is because references must refer to something and therefore cannot be default constructed. Once you are in the constructor body, all your data members have been initialized. Your this->cam = cam;
line would really be an assignment, assigning the value referred to by cam
to whatever this->cam
refers to.
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