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  1. #include <iostream>
  2. #include <set>
  3. #include <string>
  4. #include <type_traits>
  5.  
  6. template <typename T>
  7. struct NoisyAlloc
  8. {
  9.     using size_type = std::size_t;
  10.     using difference_type = std::ptrdiff_t;
  11.  
  12.     using value_type = T;
  13.     using pointer = T *;
  14.     using const_pointer = const T *;
  15.     using reference = T &;
  16.     using const_reference = const T &;
  17.  
  18.     template <typename U> struct rebind { using other = NoisyAlloc<U>; };
  19.  
  20.     T * allocate(std::size_t n)
  21.     {
  22.         std::cout << "Allocating " << n << " units.\n";
  23.         return static_cast<T *>(::operator new(n * sizeof(T)));
  24.     }
  25.     void deallocate(T * p, std::size_t n)
  26.     {
  27.         std::cout << "Freeing " << n << " units.\n";
  28.         ::operator delete(p);
  29.     }
  30.  
  31.     using is_always_equal = std::true_type;
  32.     bool operator==(const NoisyAlloc&) const { return true; }
  33.     bool operator!=(const NoisyAlloc&) const { return false; }
  34. };
  35.  
  36.  
  37. int main()
  38. {
  39.     std::set<unsigned char> s;
  40.     for (unsigned int c = 0; c < 0x100; ++c) s.insert(c);
  41.  
  42.     std::basic_string<char, std::char_traits<char>, NoisyAlloc<char>> str(s.begin(), s.end());
  43.  
  44.     //std::basic_string<char, std::char_traits<char>, NoisyAlloc<char>> str;
  45.     //str.reserve(500);
  46.     //str.append(s.begin(), s.end());
  47.     //str.assign(s.begin(), s.end());
  48.     //str.insert(str.end(), s.begin(), s.end());
  49.     //for (unsigned char c : s) str.push_back(c);
  50. }
Success #stdin #stdout 0s 3460KB
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stdin
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Standard input is empty
stdout
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Allocating 269 units.
Freeing 269 units.
https://ideone.com/nLE7A2
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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