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  1. #include <iostream>
  2. #include <inttypes.h>
  3. #include <type_traits>
  4.  
  5. template <int F>
  6. struct fp
  7. {
  8. 	constexpr static const unsigned int BITSF = F;
  9. 	int32_t s;
  10.  
  11. 	template<class B = int, typename std::enable_if<!std::is_same<B, int32_t>::value>::type...>
  12. 	fp(const int & b) : s(((int32_t)b) << F) { }
  13. 	fp(const int32_t & b) : s(b << F) { }
  14. 	fp(const float & b) : s(b * (1 << F)) { }
  15. 	template<int T>
  16. 	fp(const fp<T> & b) { *this = b; }
  17.  
  18. 	template<class B = int, typename std::enable_if<!std::is_same<B, int32_t>::value>::type...>
  19. 	fp & operator=(const int & b) { s = ((int32_t)b) << F; return *this; }
  20. 	fp & operator=(const int32_t & b) { s = b << F; return *this; }
  21. 	fp & operator=(const float & b) { s = b * (1 << F); return *this; }
  22. 	fp & operator=(const fp & b) { s = b.s; return *this; }
  23.  
  24. 	template<int T>
  25. 	fp & operator=(const fp<T> & b)
  26. 	{
  27. 		if (T > F) { s = b.s >> (T - F); }
  28. 		else if (T < F) { s = b.s << (F - T); }
  29. 		else { s = b.s; }
  30. 		return *this;
  31. 	}
  32.  
  33. 	friend std::ostream & operator<<(std::ostream & os, const fp<F> & a) { os << a.s; return os; }
  34. };
  35.  
  36. using fp824 = fp<24>;
  37. using fp1616 = fp<16>;
  38. using fp248 = fp<8>;
  39.  
  40. int main() {
  41. 	// your code goes here
  42. 	fp1616 a0(0); // error: ambiguous?!
  43. 	fp1616 a1(1); // error: ambiguous?!
  44. 	fp1616 a2(2); // error: ambiguous?!
  45. 	fp1616 a3(-2.5f);
  46. 	std::cout << a0 << std::endl;
  47. 	std::cout << a1 << std::endl;
  48. 	std::cout << a2 << std::endl;
  49. 	std::cout << a3 << std::endl;
  50. 	a0 = 5; // error: ambiguous?!
  51. 	a0 = 0; // error: ambiguous?!
  52. 	a0 = 3.4f;
  53. 	fp824 b1(1.2f);
  54. 	fp1616 b2(b1);
  55. 	fp248 b3(b2);
  56. 	b1 = b3;
  57. 	b1 = b2;
  58. 	return 0;
  59. }
Success #stdin #stdout 0s 16064KB
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stdin 
Standard input is empty
stdout 
0
65536
131072
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https://ideone.com/k7UbR5
language:
C++ (gcc 8.3)
created:
7 years ago
visibility:
public

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