我正在尝试创建.dll文件。我定义了一个类
class Contactmodel
public:
Contactmodel();
virtual ~Contactmodel();
然后，我尝试创建此类的实例
virtual Contactmodel *clone() const {return new Contactmodel();}
但是当我编译时，它会导致错误：创建抽象类的实例时不允许使用抽象类类型的对象
您能否告诉我创建实例以及如何修复它我做错了什么？谢谢！
我的头文件
#pragma once
// contactmodelCohesive.h
#include "contactmodel/src/contactmodelmechanical.h"
#ifdef Cohesive_LIB
# define Cohesive_EXPORT EXPORT_TAG
#elif defined(NO_MODEL_IMPORT)
# define Cohesive_EXPORT
#else
# define Cohesive_EXPORT IMPORT_TAG
#endif
namespace cmodelsxd {
using namespace itasca;
class ContactModelCohesive : public ContactModelMechanical {
public:
Cohesive_EXPORT ContactModelCohesive();
Cohesive_EXPORT virtual ~ContactModelCohesive();
virtual void copy(const ContactModel *c);
virtual void archive(ArchiveStream &);
virtual QString getName() const { return "Cohesive"; }
virtual void setIndex(int i) { index_=i;}
virtual int getIndex() const {return index_;}
enum PropertyKeys {
kwKn=1
, kwKs
, kwFric
, kwForce
, kwMoment
, kwState
, kwRGap
, kwConRad
, kwSig
, kwTau
, kwEmod
, kwKRatio
, kwTenStrength
, kwCoh
, kwPhiF
, kwPhiD
, kwInelasDeform
, kwDamagevar
, kwAlpha
, kwLamda
, kwwsig
, kwwcoh
};
virtual QString getProperties() const {
return " kn"
",ks"
",fric"
",coh_force"
",coh_moment"
",state"
",rgap"
",con_rad"
",sigma"
",tau"
",emod"
",kratio"
",ten_strength"
",cohesion"
",phi_f"
",phi_d"
",in_deform"
",D_var"
",alpha"
",lamda"
",w_sig"
",w_coh";
}
enum FishCallEvents { fActivated=0, fBondBreak };
virtual QString getFishCallEvents() const { return "contact_activated,contact_break"; }
virtual QVariant getProperty(uint i,const IContact *) const;
virtual bool getPropertyGlobal(uint i) const;
virtual bool setProperty(uint i,const QVariant &v,IContact *);
virtual bool getPropertyReadOnly(uint i) const;
enum MethodKeys { kwDeformability=1
, kwcohBond
, kwcohUnbond
};
virtual QString getMethods() const {
return "deformability"
",bond"
",unbond";
}
virtual QString getMethodArguments(uint i) const;
virtual bool setMethod(uint i,const QVector<QVariant> &vl,IContact *con=0); // Base 1 - returns true if timestep contributions need to be updated
virtual uint getMinorVersion() const;
virtual bool validate(ContactModelMechanicalState *state,const double ×tep);
//virtual bool endPropertyUpdated(const QString &name,const IContactMechanical *c);
virtual bool forceDisplacementLaw(ContactModelMechanicalState *state,const double ×tep);
virtual DVect2 getEffectiveTranslationalStiffness() const { DVect2 ret = effectiveTranslationalStiffness_; return ret;}
virtual DAVect getEffectiveRotationalStiffness() const {if (!cohProps_) return DAVect(0.0); return cohProps_->coh_AngStiff_;}
virtual ContactModelCohesive *clone() const { return NEWC(ContactModelCohesive()); }
virtual double getActivityDistance() const {return rgap_;}
virtual bool isOKToDelete() const { return !isBonded(); }
virtual void resetForcesAndMoments() { cohF(DVect(0.0)); cohM(DAVect(0.0));}
virtual bool checkActivity(const double &gap) { return (gap <= rgap_ || isBonded()); }
virtual bool isBonded() const { return cohProps_ ? (cohProps_->coh_state_==3) : false; }
bool hasPBond() const {return cohProps_ ? true:false;}
const double & rgap() const {return rgap_;}
void rgap(const double &d) {rgap_=d;}
int cohState() const {return hasPBond() ? cohProps_->coh_state_: 0;}
void cohState(int i) { if(!hasPBond()) return; cohProps_->coh_state_=i;}
double cohKn() const {return (hasPBond() ? (cohProps_->coh_kn_) : 0.0);}
void cohKn(const double &d) { if(!hasPBond()) return; cohProps_->coh_kn_=d;}
double cohKs() const {return (hasPBond() ? (cohProps_->coh_ks_) : 0.0);}
void cohKs(const double &d) { if(!hasPBond()) return; cohProps_->coh_ks_=d;}
double cohFric() const {return (hasPBond() ? (cohProps_->coh_fric_) : 0.0);}
void cohFric(const double &d) { if(!hasPBond()) return; cohProps_->coh_fric_=d;}
double cohTen() const {return (hasPBond() ? (cohProps_->coh_ten_) : 0.0);}
void cohTen(const double &d) { if(!hasPBond()) return; cohProps_->coh_ten_=d;}
double cohLamda() const {return (hasPBond() ? (cohProps_->coh_lamda_) : 0.0);}
void cohLamda(const double &d) { if(!hasPBond()) return; cohProps_->coh_lamda_=d;}
double cohAlpha() const {return (hasPBond() ? (cohProps_->coh_alpha_) : 0.0);}
void cohAlpha(const double &d) { if(!hasPBond()) return; cohProps_->coh_alpha_=d;}
double cohInelas() const {return (hasPBond() ? (cohProps_->coh_inelas_) : 0.0);}
void cohInelas(const double &d) { if(!hasPBond()) return; cohProps_->coh_inelas_=d;}
double cohDvar() const {return (hasPBond() ? (cohProps_->coh_dvar_) : 0.0);}
void cohDvar(const double &d) { if(!hasPBond()) return; cohProps_->coh_dvar_=d;}
double cohCoh() const {return (hasPBond() ? (cohProps_->coh_coh_) : 0.0);}
void cohCoh(const double &d) { if(!hasPBond()) return; cohProps_->coh_coh_=d;}
double cohPhiD() const {return (hasPBond() ? (cohProps_->coh_phid_) : 0.0);}
void cohPhiD(const double &d) { if(!hasPBond()) return; cohProps_->coh_phid_=d;}
double cohPhiF() const {return (hasPBond() ? (cohProps_->coh_phif_) : 0.0);}
void cohPhiF(const double &d) { if(!hasPBond()) return; cohProps_->coh_phif_=d;}
double cohwsig() const {return (hasPBond() ? (cohProps_->w_sig) : 0.0);}
void cohwsig(const double &d) { if(!hasPBond()) return; cohProps_->w_sig=d;}
double cohwcoh() const {return (hasPBond() ? (cohProps_->w_coh) : 0.0);}
void cohwcoh(const double &d) { if(!hasPBond()) return; cohProps_->w_coh=d;}
DVect cohF() const {return hasPBond() ? cohProps_->coh_F_: DVect(0.0);}
void cohF(const DVect &f) { if(!hasPBond()) return; cohProps_->coh_F_=f;}
DAVect cohM() const {return hasPBond() ? cohProps_->coh_M_: DAVect(0.0);}
void cohM(const DAVect &m) { if(!hasPBond()) return; cohProps_->coh_M_=m;}
DVect2 cohTransStiff() const {return hasPBond() ? cohProps_->coh_TransStiff_: DVect2(0.0);}
void cohTransStiff(const DVect2 &f) { if(!hasPBond()) return; cohProps_->coh_TransStiff_=f;}
DAVect cohAngStiff() const {return hasPBond() ? cohProps_->coh_AngStiff_: DAVect(0.0);}
void cohAngStiff(const DAVect &m) { if(!hasPBond()) return; cohProps_->coh_AngStiff_=m;}
const DVect2 & effectiveTranslationalStiffness() const {return effectiveTranslationalStiffness_;}
void effectiveTranslationalStiffness(const DVect2 &v ) {effectiveTranslationalStiffness_=v;}
private:
static int index_;
struct cohProps {
cohProps() : coh_kn_(0.0), coh_ks_(0.0), coh_fric_(0.0), coh_state_(0), coh_ten_(0.0), coh_coh_(0.0),
coh_alpha_(1.0), coh_lamda_(0.0), coh_phid_(0.0), coh_phif_(0.0), coh_dvar_(0.0), coh_inelas_(0.0),
coh_F_(DVect(0.0)), coh_M_(DAVect(0.0)), coh_TransStiff_(0.0), coh_AngStiff_(0.0) {}
// parallel bond
int coh_state_; // Contact mode - 0 (NBNF), 1 (NBFT), 2 (NBFS), 3 (B)
double coh_kn_; // normal stiffness
double coh_ks_; // shear stiffness
double kn0;
double ks0;
double coh_fric_; // Moment contribution factor
double coh_ten_; // normal strength
double coh_coh_; // friction angle
double ten0;
double coh0;
double coh_inelas_; // friction angle
double coh_alpha_; // soften normal stiffness
double coh_lamda_; // soften normal stiffness
double coh_phid_; // soften normal stiffness
double phid0;
double coh_phif_; // soften normal stiffness
double coh_dvar_; // soften normal stiffness
DVect coh_F_; // Force in parallel bond
DAVect coh_M_; // moment in parallel bond
double mn;
double ms;
double w_sig;
double w_coh;
DVect2 coh_TransStiff_; // (Normal,Shear) Translational stiffness of the parallel bond
DAVect coh_AngStiff_; // (Normal,Shear) Rotational stiffness of the parallel bond
};
void updateEffectiveStiffness(ContactModelMechanicalState *state);
DVect3 cohData(const IContactMechanical *con) const; // Bond area and inertia
DVect2 cohSMax(const IContactMechanical *con) const; // Maximum stress (tensile,shear) at bond periphery
double cohShearStrength(const double &cohArea) const; // Bond shear strength
double rgap_; // reference gap for the linear part
cohProps * cohProps_; // The parallel bond properties
DVect2 effectiveTranslationalStiffness_;
}; //ContactModelCohesive
} // cmodelsxd
答案 0 :(得分：1)
拥有抽象基类的原因是提供具体类必须实现的接口。您不应该创建抽象基类的实例。
使clone()成为纯虚函数，不要在基类中实现它。只在具体的类中实现它。
virtual Contactmodel *clone() const = 0;
答案 1 :(得分：0)
如果Contactmodel是抽象类（即包含纯虚函数），则无法创建Contactmodel的实例。 clone通常被定义为基类中的纯虚函数，在派生中重载，如
struct IClonable
{
virtual IClonable* clone() const = 0;
virtual ~IClonable() = default;
};
class Foo: public IClonable
{
public:
Foo* clone() const override
{
return new Foo{*this};
}
};
int main()
{
Foo* foo = new Foo;
Foo* clone = foo->clone();
delete clone;
delete foo;
}
或者，使用智能指针
#include <memory>
struct IClonable
{
virtual std::unique_ptr<IClonable> clone() const = 0;
virtual ~IClonable() = default;
};
class Foo: public IClonable
{
public:
std::unique_ptr<IClonable> clone() const override
{
return std::make_unique<Foo>(*this);
}
};
int main()
{
std::unique_ptr<IClonable> up_foo{new Foo};
std::unique_ptr<IClonable> up_clone = up_foo->clone();
}