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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. struct A {
  5. 	virtual void f(int a=1) = 0;    
  6. };
  7. struct B:A {
  8. 	void f(int a) override ;     
  9. };
  10. struct C:A {
  11. 	void f(int a=2) override ;     
  12. };
  13. void B::f(int a)        // definition 
  14. {
  15. 	cout<<"B"<<a<<endl; 
  16. }
  17. void C::f(int a)        // definition 
  18. {
  19. 	cout<<"C"<<a<<endl; 
  20. }
  21. int main() {
  22. 	B b; 
  23. 	C c; 
  24. 	A *x=&c, *y=&b;    // points to the same objects but using a polymorphic pointer
  25. 	x->f();  // default value defined for A::f() but with the implementation of C ==> C1   
  26. 	y->f();  // default value defined for A::f() but with the implementation of B ==> B1
  27. //	b.f();  // default not defined for B::f();   
  28. 	c.f();  // default value defined for C::f(); ==> C2
  29. 	return 0;
  30. }
Success #stdin #stdout 0s 15240KB
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Standard input is empty
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C1
B1
C2
https://ideone.com/jvx2kC
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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