分配抽象类类型错误的对象

Question

嗨,我收到以下错误,我真的不确定为什么.

class InteSiVis: public ofBaseApp //{
,  public ofxMidiListener{

当我从ofxMidiListener类继承类inresivis并且在主源文件中出现以下错误时会发生这种情况

int main(){

ofSetupOpenGL(1920,1080, OF_WINDOW);            
ofRunApp( new InteSiVis()); // <-------- The error is here Allocating object of type abstract

}

这真的令人困惑,因为我已经用另一个例子以确切的方式尝试了这个并且没有得到这个错误.

class testApp : public ofBaseApp, public ofxMidiListener {

int main(){
    ofSetupOpenGL(640, 480, OF_WINDOW);
    ofRunApp(new testApp());
}

你能不能给我一个想法,为什么我得到这个错误我正在以完全相同的方式调用这个类.提前致谢.

/// ----------------------------------编辑InteSiVis.h

class InteSiVis: public ofBaseApp //{
,  public ofxMidiListener{

public:
    InteSiVis() ;

    void setup();
    void update();
    void draw();
    void exit();

    void keyPressed(int key);
    void keyReleased(int key);

    // Make an Array of Particle Systems
    vector<FluidBodySim> mArrayFluidBodySim;

    FluidBodySim        mFluidBodySim       ;   ///< Simulation of fluid and rigid bodies

    int                 mStatusWindow       ;   ///< Identifier for status window
    unsigned            mFrame              ;   ///< Frame counter
    double              mTimeNow            ;   ///< Current virtual time
    int                 mMouseButtons[3]    ;   ///< Mouse buttons pressed
    bool                mInitialized        ;   ///< Whether this application has been initialized
    int                 mScenario           ;   ///< Which scenario is being simulated now

// Scene stuff
    ofEasyCam mEasyCam;
    ofLight light;

// Setting Shader stuff
    ofShader shader;
    ofxPostProcessing post;

// Sound

    float   * lAudioOut; /* outputs */
    float   * rAudioOut;

    float * lAudioIn; /* inputs */
    float * rAudioIn;

    int     initialBufferSize; /* buffer size */
    int     sampleRate;

    double wave,sample,outputs[2];

    maxiSample piano_A1, piano_AS1, piano_B1, piano_C1, piano_CS1, piano_D1, piano_DS1, piano_E1, piano_F1, piano_FS1, piano_G1, piano_GS1;

    vector<maxiPitchStretch<grainPlayerWin>*> stretches;

    maxiPitchStretch<grainPlayerWin> *ts, *ts2, *ts3, *ts4, *ts5;

    int nAverages;
    float *ifftOutput;
    int ifftSize;

//    // Playing the Wav Files
    void audioOut(float *output, int bufferSize, int nChannels);

    double speed, grainLength, rate;

    ofxMaxiFFT fft;
    ofxMaxiFFTOctaveAnalyzer oct;
    int current;
    double pos;


} ;

testApp.h

class testApp : public ofBaseApp, public ofxMidiListener {

public:

    void setup();
    void draw();
    void exit();

    void keyPressed(int key);
    void keyReleased(int key);

    void mouseMoved(int x, int y );
    void mouseDragged(int x, int y, int button);
    void mousePressed(int x, int y, int button);
    void mouseReleased();


    stringstream text;

    vector<ParticleSystem> ps;

    //----------------------Sound---------------------------

    void newMidiMessage(ofxMidiMessage& eventArgs);


    ofxMidiIn midiIn;
    ofxMidiOut midiOut;
    ofxMidiMessage midiMessage;

    void audioOut(float *output, int bufferSize, int nChannnels);

};

// ---------------- VIRTUAL FUNCTION vorticitydistribution.h

class IVorticityDistribution
{
    public:
        virtual Vec3 GetDomainSize( void ) const = 0 ;
        virtual void AssignVorticity( Vec3 & vorticity , const Vec3 & position , const Vec3 & vCenter ) const = 0 ;
} ;

class JetRing : public IVorticityDistribution
{
    public:
        /*! \brief Initialize parameters for a vortex ring (using a different formula from the other).

            The vorticity profile resulting from this is such that the induced velocity is in [0,1].

            \param fRadiusSlug - radius of central region where velocity is constant

            \param fThickness - thickness of vortex ring, i.e. radius of annular core

            \param vDirection - vector of ring axis, also vector of propagation

            \param fSpeed   - speed of slug

        */
        JetRing( const float & fRadiusSlug , const float & fThickness , const Vec3 & vDirection )
            : mRadiusSlug( fRadiusSlug )
            , mThickness( fThickness )
            , mRadiusOuter( mRadiusSlug + mThickness )
            , mDirection( vDirection )
        {
        }

        virtual Vec3 GetDomainSize( void ) const
        {
            const float boxSideLength   = 2.f * ( mRadiusOuter ) ;    // length of side of virtual cube
            return Vec3( 1.0f , 1.0f , 1.0f ) * boxSideLength ;
        }

        virtual void AssignVorticity( Vec3 & vorticity , const Vec3 & position , const Vec3 & vCenter ) const
        {

} ;

Answer 1

这就是事情的运作方式:

class Base
{
        public:
         const std::string SayHi() { return "Hi"; } // a normal non-virtual method            
         virtual std::string GetName() { return ("Base"); } // a normal virtual method
         virtual int GetValue() = 0; // a pure virtual method
}; 

当你像这样声明testApp时class testApp : public Base { ... };:

正常的非虚方法是继承的,因为它们在Base中声明,并且是不可变的.

普通的虚方法在Base中声明它们是继承的,你可以使用它们>因为它们已经被声明,或者重新定义它们以适合特定的目的.

没有定义纯虚方法,父类只说"如果你继承我,你必须自己实现,严格匹配我的原型(我如何定义它们)

如果您不遵守这些规则,您将收到错误.

现在,你必须要确保有内部没有纯虚methodes ofBaseApp既不ofxMidiListener未落实到儿童类.

由于您声明类testApp没有执行任何错误,因此您必须在您忘记实现的父类中使用InteSiVis中的纯虚方法.