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  1. #include <iostream>
  2. #include <string>
  3. #include <type_traits>
  4.  
  5. using namespace std;
  6.  
  7. template<typename U>
  8. class A
  9. {
  10. public:
  11. 	static_assert(!std::is_same<int, U>::value && !std::is_same<double,U>::value,
  12.                                "Template argument cannot be <int> or <double>.");
  13. 	A(const U& u) : u(u) {};
  14. 	explicit operator U() { return u; }
  15. 	explicit operator int() { return i; }
  16. 	explicit operator double() { return d; }
  17.  
  18. private:
  19. 	U u;
  20. 	int i = 5;
  21. 	double d = 3.14;
  22. };
  23.  
  24. int main()
  25. {
  26. 	A<string> a("name");
  27. 	cout << double(a) << '\n';
  28. 	cout << int(a) << '\n';
  29. 	cout << string(a) << '\n';
  30. 	return 0;
  31. }
  32.  
Success #stdin #stdout 0s 3412KB
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stdin
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Standard input is empty
stdout
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3.14
5
wow
https://ideone.com/W2n8Qj
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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