虚拟克隆方法出错

Question

我正在制作一个用虚拟副本构造函数定义某些类的标题，代码如下：

 #ifndef PAYOFF_H
    #define PAYOFF_H

    class Pay_Off{
       public:
      // enum Option_Type {call, put};
       Pay_Off(/*double Strike_, Option_Type Option_*/){};
       virtual double operator()(double Spot) const=0;
       virtual ~Pay_Off(){}
      virtual  Pay_Off* clone() const=0;
      private:
   };

  class Pay_Off_Call: public Pay_Off{
    public:
      Pay_Off_Call(double Strike_);
      virtual double operator()(double Spot) const;
      virtual Pay_Off* clone() const;
      virtual ~Pay_Off_Call(){}
    private:
      double Strike;
  };

  class Pay_Off_Put:public Pay_Off{
    public:
      Pay_Off_Put(double Strike_);
      virtual double operator()(double Spot) const;
      virtual Pay_Off* clone const;
      virtual ~Pay_Off_Put(){}
    private:
      double Strike;
  };
  #endif

编译时不断弹出错误：

error: ‘clone’ declared as a ‘virtual’ field
     virtual Pay_Off* clone const;

我不了解它为什么会发生，我该如何解决？

Answer 1

在班级Pay_Off_Put

virtual Pay_Off* clone const;

您在方法声明中错过了()。没有它，编译器会将其视为成员变量，它不能是虚拟的。因此它显示了这个错误。

将其声明为

virtual Pay_Off* clone() const;

Answer 2

将virtual Pay_Off* clone const;替换为virtual Pay_Off* clone() const;并进行编译。