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  1. #include <iostream>
  2. #include <vector>
  3. #include <type_traits>
  4. using namespace std;
  5.  
  6.  
  7. template<typename In>
  8. auto foo(In input, std::true_type) {
  9. 	return input[0];
  10. }
  11. template<typename In>
  12. auto foo(In input, std::false_type) {
  13. 	return input;
  14. }
  15. template<bool IsVector, typename In>
  16. auto foo(In input) {
  17. 	using tag = typename conditional<IsVector, true_type, false_type>::type;
  18. 	return foo(input, tag{});
  19. }
  20.  
  21.  
  22. int main() {
  23. 	cout << foo<true>(vector<double>{{1, 2 , 3}}) << endl;
  24. 	cout << foo<false>(4.5) << endl;
  25. 	return 0;
  26. }
Success #stdin #stdout 0s 3460KB
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Standard input is empty
stdout
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1
4.5
https://ideone.com/zHTNhf
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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