Is bad programming practice a mix of virtual and non-virtual functions in a base class?

Question

I have a base class Base, which I declare as several polymorphic subclasses. Some of the functions of the base class are pure virtual, while others are used directly by the subclass.

(All this in C ++)

So for example:

class Base
{
protected:
     float my_float;
public:

    virtual void Function() = 0;

    void SetFloat(float value){ my_float = value}

}

class subclass : public Base
{

  void Function(){ std::cout<<"Hello, world!"<<std::endl; }
}

class subclass2 : public Base
{

  void Function(){ std::cout<<"Hello, mars!"<<std::endl; }
}

So, as you can see, subclasses would rely on the base class for a function that sets "my_float" but would be polymorphic with respect to another function.

So I wonder, this is a good practice. If you have an abstract base class, should you make it completely abstract, or is it ok to make such a hybrid approach?

Answer 1

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class DataStorage {
private:
  float data_;
public:
  DataStorage()
  : data_(0.f) {
  }

  void setFloat(float data) {
    data_ = data;
  }
};

class NotASubclass1 {
private:
  DataStorage data_;
public:
  void SetFloat(float value){ data_.setFloat(value); }  
  ...
}

class NotASubclass2 {
private:
  DataStorage data_;
public:
  void SetFloat(float value){ data_.setFloat(value); }  
  ...
}

Answer 2

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