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  1. #include <iostream>
  2.  
  3. class Animal
  4. {
  5. public:
  6. 	virtual ~Animal(){}
  7. };
  8.  
  9. class Dog : public Animal
  10. {
  11. public:
  12. 	virtual void woof() { }
  13. };
  14.  
  15. class Cat : public Animal
  16. {
  17. public:
  18. 	virtual void meow() { }
  19. };
  20.  
  21. int main()
  22. {
  23. 	Cat felix;
  24. 	Cat* the_cat = &felix;
  25. 	// "normal" cast, which disallows casting between unrelated class hierarchies,
  26. 	// but while downcasting assumes the programmer knows 
  27. 	Dog* the_dog_1 = static_cast<Dog*>(the_cat);
  28. 	// your cast with testing validity at runtime
  29. 	// (doesn't fail at compile time, because there may be a CatDog
  30. 	// derived from Cat and Dog in other translation unit)
  31. 	Dog* the_dog_2 = dynamic_cast<Dog*>(the_cat);
  32. 	// "everything goes" byte reinterpretation cast
  33. 	Dog* the_dog_3 = reinterpret_cast<Dog*>(the_cat);
  34.  
  35. 	the_dog_1->woof();
  36.  
  37. 	if(the_dog_2)
  38. 		the_dog_2->woof();
  39.  
  40. 	the_dog_3->woof();
  41. }
Compilation error #stdin compilation error #stdout 0s 0KB
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stdin
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Standard input is empty
compilation info 
prog.cpp: In function 'int main()':
prog.cpp:27:44: error: invalid static_cast from type 'Cat*' to type 'Dog*'
  Dog* the_dog_1 = static_cast<Dog*>(the_cat);
                                            ^
stdout
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Standard output is empty
https://ideone.com/RxrKkk
language:
C++ (gcc 8.3)
created:
9 years ago
visibility:
public

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