c++ - 为什么我的虚拟功能不起作用？

Question

我有一个名为 camera 的抽象类，PointCamera 将其用作其父类(super class)。出于某种原因，其中一个虚函数在调试器中抛出错误，并告诉我它正在尝试执行 0x00000000。仅当所讨论的函数是抽象类中声明的最后一个函数时才会发生这种情况。如果我切换声明顺序，那么新的 last 函数将出于同样的原因不起作用。为什么会这样？

class Camera
{
public:
    //Default constructor
    Camera();

    //Assignment operator
    virtual Camera* clone() = 0;

    //Get a ray
    virtual void KeyCamera() = 0;
    virtual void GetRay(float x, float y, Ray* out) = 0;
};

和

class PointCamera: Camera
{
private:
    //Camera location, target, and direction
    Vector loc, dir, tar, up;
    //Orthonormal vectors
    Vector u, v, w;
    //Virtual plane size
    float plane_width, plane_height;
    int width, height;
    //Distance from the camera point to the virtual plane
    float lens_distance;
    //Pixel size
    float pixelSizex, pixelSizey;

public:
    //Default constructor
    PointCamera();
    //Constructors
    PointCamera(Vector& iloc, Vector& itar);
    PointCamera(Vector& iloc, Vector& itar, Vector& idir);

    //Destructor
    ~PointCamera();

    //Modifiers
    void SetDirection(Vector& idir);
    void SetUp(Vector& iup);
    void SetTarget(Vector& itar);
    void SetLocation(Vector& iloc);
    void SetPlane(int iheight, int iwidth, float iplane_width = -1.0f, float iplane_height = -1.0f);
    void SetLensDistance(float ilens_distance);

    //Implememented method
    virtual void GetRay(float x, float y, Ray* out);
    virtual void SetupRay(Ray* out);

    //Compute orthonormal vectors
    virtual void KeyCamera();
};

Answer 1

Ok I just re-compiled everything and it worked. I don't know what went wrong. Thanks for your suggestions.

检查您的依赖项。我敢打赌应该取决于头文件的东西不是。当您进行干净构建时，依赖于该头文件的源代码文件已更新。