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  1. #include <iostream>
  2. #include <type_traits> 
  3.  
  4. template<int I,class T> 
  5. struct static_case { 
  6. 	static constexpr int value = I; 
  7. 	using type = T; 
  8. }; 
  9.  
  10.  
  11. template<int I, class DefaultType, class Case1, class... OtherCases> 
  12. struct static_switch{ 
  13. 	using type = typename std::conditional< I==Case1::value ,  
  14. 					typename Case1::type, 
  15. 					typename static_switch<I,DefaultType,OtherCases...>::type 
  16. 				     >::type; 
  17. }; 
  18.  
  19.  
  20. template<int I, class DefaultType, class LastCase> 
  21. struct static_switch<I,DefaultType,LastCase> { 
  22. 	using type = typename std::conditional< I==LastCase::value ,  
  23. 					typename LastCase::type, 
  24. 					DefaultType 
  25. 				     >::type; 
  26. }; 
  27.  
  28.  
  29. template<class T>
  30. typename static_switch<sizeof(T)
  31.             ,int // default case
  32.             ,static_case<sizeof(char),char>
  33.             ,static_case<sizeof(short),short>
  34.             ,static_case<sizeof(long),long>
  35.             ,static_case<sizeof(long long),long long>
  36.             >::type foo(T bar){ return reinterpret_cast<decltype(foo(bar))&>(bar);}
  37.  
  38.  
  39. auto val = foo(13.0);
  40. static_assert(std::is_same<long long, decltype(val)>::value,"Not converted to long long!");
  41.  
  42. using namespace std;
  43.  
  44. int main() {
  45. 	// your code goes here
  46. 	return 0;
  47. }
Success #stdin #stdout 0s 3092KB
comments ()
stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/qiJ0BI
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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