C1125: Cannot instantiate abstract class as a type of explicit conversion

[ERROR]

Description

An abstract class may not be used as a type of an explicit conversion.

Example

  class A{

  public:

    virtual void f(void) = 0; //pure virtual function ==> 
  A is an abstract class

};

  class B : public A{

  public:

    void f(void){}

};

  void main(void){

    A *pa;

    B b;

    pa = &amp;(A)b;

Tips

Use a pointer/reference to the object

  void main(void){

    A *pa;

    B b;

    pa = (A *)b;