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  1. #include <iostream>
  2. #include <vector>
  3.  
  4. using namespace std;
  5.  
  6. template <typename T, typename Enable=void>
  7. struct foo {
  8.   void operator()() const { cout << "unspecialized" << endl; }
  9. };
  10.  
  11. template <typename T>
  12. struct foo<T, enable_if_t<
  13.   is_integral<T>::value
  14. >>{
  15.   void operator()() const { cout << "is_integral" << endl; }
  16. };
  17.  
  18. template <typename T>
  19. struct foo<T, enable_if_t<
  20.   sizeof(T) == 4
  21.     and not is_integral<T>::value
  22. >>{
  23.   void operator()() const { cout << "size 4" << endl; }
  24. };
  25.  
  26. template <typename T>
  27. struct foo<T, enable_if_t<
  28.   is_fundamental<T>::value
  29.     and not (sizeof(T) == 4)
  30.     and not is_integral<T>::value
  31. >>{
  32.   void operator()() const { cout << "fundamental" << endl; }
  33. };
  34.  
  35. int main() {
  36.   foo<int>()();
  37.   foo<float>()();
  38.   foo<double>()();
  39.   foo<vector<int>>()();
  40. }
  41.  
Success #stdin #stdout 0s 3456KB
comments (?)
stdin
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Standard input is empty
stdout
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is_integral
size 4
fundamental
unspecialized
https://ideone.com/QQlSWZ
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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