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  1. #include <iostream>
  2. #include <list>
  3. #include <vector>
  4.  
  5. template <typename T>
  6. class test
  7. {
  8. public:
  9.   template <typename I>
  10.   auto call(I first, I last) const
  11.    -> decltype(T()(first, last))
  12.   {
  13.     return T()(first, last);
  14.   }
  15. };
  16.  
  17. template <typename T>
  18. struct sum
  19. {
  20.   template <typename I>
  21.   T operator()(I first, I last) const
  22.   {
  23.     T res = 0;
  24.     while (first != last)
  25.     {
  26.       res += *first;
  27.       ++first;
  28.     }
  29.     return res;
  30.   }
  31. };
  32.  
  33. int main()
  34. {
  35.   test<sum<double>> t;
  36.   double a[] {1.,2.,3.};
  37.   std::cout << "Test (array) => " << t.call(a, a+3) << std::endl;
  38.   std::vector<double> v {1.,2.,3.};
  39.   std::cout << "Test (vector) => " << t.call(v.begin(), v.end()) << std::endl;
  40.   std::list<double> l {1.,2.,3.};
  41.   std::cout << "Test (list) => " << t.call(l.begin(), l.end()) << std::endl;
  42. }
  43.  
  44.  
Success #stdin #stdout 0s 3472KB
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stdin
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Standard input is empty
stdout
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Test (array) => 6
Test (vector) => 6
Test (list) => 6
https://ideone.com/0PIUCD
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
secret

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