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  1. #include <iostream>
  2. #include "boost/optional.hpp"
  3. using namespace std;
  4.  
  5. struct No_data{
  6. 	operator bool() const{
  7. 		return false;
  8. 	}
  9. };
  10.  
  11. template<typename T>
  12. struct Data {
  13. 	T t;
  14. 	operator bool() const {
  15. 		return true;
  16. 	}
  17. };
  18.  
  19.  
  20. template<typename T>
  21. struct myOptional {
  22. 	union {
  23. 		Data<T> t;
  24. 		No_data nd;
  25. 	} data;
  26. };
  27. int main(){
  28. 	myOptional<bool> ob;
  29. 	cout << sizeof(myOptional<bool>) << endl;
  30. 	return 0;
  31. }
Success #stdin #stdout 0s 3096KB
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https://ideone.com/OBSchN
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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