class - C++ Call subclass method from superclass -

i have code of following style:

class subclass; class superclass;  class superclass {  private:      void bar() {          subclass().foo();     } };  class subclass : superclass {  public:      void foo() {}; }; 

so have superclass want call method foo() of subclass. vs 2012 gives me following errors:

error 1 error c2514: 'subclass' : class has no constructors.

error 2 error c2228: left of '.foo' must have class/struct/union.

what correct structure want do?

you can't this. must (at least) declare method in base class. example:

#include <iostream>  class superclass  { public:     void bar()      {         foo();     } private:     virtual void foo() // pure virtual, if     {         std::cout << "superclass::foo()" << std::endl;     } };  class subclass : public superclass // not forget inherit public { public:     virtual void foo() { std::cout << "subclass::foo()" << std::endl; } };  int main() {     superclass* ptest = new subclass;      ptest -> bar();      delete ptest; } 

will print subclass::foo().