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  1. #include <cstdio>
  2. #include <cstdlib>
  3. #include <utility>
  4.  
  5.  
  6. template <typename T>
  7. struct default_delete {
  8.     void operator ()(T *ptr) {
  9.         delete ptr;
  10.     }
  11. };
  12.  
  13. template <typename T, typename Deleter = default_delete<T>>
  14. class unique_ptr {
  15. public:
  16.     unique_ptr(T* resource = nullptr, Deleter deleter = Deleter{})
  17.         : resource{resource}, deleter{deleter} {}
  18.  
  19.     unique_ptr(const unique_ptr&) = delete;
  20.     unique_ptr(unique_ptr&& other) 
  21.         : resource{std::move(other.resource)},
  22.           deleter{std::move(other.deleter)} {}
  23.  
  24.     unique_ptr& operator=(const unique_ptr&) = delete;
  25.     unique_ptr& operator=(unique_ptr&& other) {
  26.         using std::swap;
  27.         swap(other.resource, resource);
  28.         swap(other.deleter, deleter);
  29.     }
  30.  
  31.     ~unique_ptr() {
  32.         deleter(resource);
  33.     }
  34.  
  35.     T* get() { return resource; }
  36.     const T* get() const { return resource; }
  37.  
  38. private:
  39.     T* resource;
  40.     Deleter deleter;
  41. };
  42.  
  43. int main() {
  44.     // using default deleter
  45.     unique_ptr<int>  int_ptr(new int{});
  46.  
  47.     // using std::free to delete dynamically allocated memory
  48.     unique_ptr<int, void(*)(void *)> array_ptr(
  49.         reinterpret_cast<int *>(std::malloc(5 * sizeof(int))),
  50.         std::free);
  51.  
  52.     // using std::fclose to close an opened file
  53.     // You'll have to try this one localy - unable to open file on a server
  54.     /*
  55.     unique_ptr<FILE, int(*)(FILE *)> file_ptr(
  56.         std::fopen("my_file.txt", "w"),
  57.         std::fclose);
  58.     //*/
  59.     // use int_ptr, array_ptr, file_ptr here
  60.  
  61.     // these resources get released here, at the end of scope
  62. }
  63.  
Success #stdin #stdout 0s 4464KB
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https://ideone.com/GkqeGT
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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