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  1. #include <iostream>
  2.  
  3. // A class with a pointer and a getter that returns a reference.
  4. class A {
  5.     std::string *text;
  6. public:
  7.     std::string& GetText_old_way() { return *text; }
  8.     auto GetText_pure_auto() { return *text; }
  9.     auto GetText_pointer_arithmetic() -> decltype(*text) & { return *text; }
  10. public:
  11.     A(std::string *text): text(text) {}
  12. };
  13.  
  14. // A class with a reference and a getter that returns a pointer.
  15. class B {
  16.     std::string& text;
  17. public:
  18.     std::string *GetText_old_way() { return &text; }
  19.     auto GetText_pure_auto() { return &text; }
  20.     auto GetText_pointer_arithmetic() -> decltype(&text) { return &text; }
  21.     auto GetText_remove_reference() -> std::remove_reference_t<decltype(text)> * { return &text; }
  22. public:
  23.     B(std::string& text): text(text) {}
  24. };
  25.  
  26. int main() {
  27.     std::string text = "hello, world";
  28.  
  29.     {//TEST
  30.         A a(&text);
  31.         unsigned int i{0};
  32.  
  33.         std::cout << "-- Test 1:"<< std::endl;
  34.         ++i; std::cout << i << ". " << a.GetText_old_way() << std::endl;
  35.         ++i; std::cout << i << ". " << a.GetText_pointer_arithmetic() << std::endl;
  36.         ++i; std::cout << i << ". " << a.GetText_pure_auto() << std::endl;
  37.         std::cout << std::endl;
  38.     }
  39.  
  40.     {//TEST
  41.         B b(text);
  42.         unsigned int i{0};
  43.  
  44.         std::cout << "-- Test 2:"<< std::endl;
  45.         ++i; std::cout << i << ". " << *b.GetText_old_way() << std::endl;
  46.         ++i; std::cout << i << ". " << *b.GetText_pointer_arithmetic() << std::endl;
  47.         ++i; std::cout << i << ". " << *b.GetText_remove_reference() << std::endl;
  48.         ++i; std::cout << i << ". " << *b.GetText_pure_auto() << std::endl;
  49.         std::cout << std::endl;
  50.     }
  51.  
  52.     return 0;
  53. }
Success #stdin #stdout 0s 15240KB
comments (?)
stdin
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Standard input is empty
stdout
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-- Test 1:
1. hello, world
2. hello, world
3. hello, world

-- Test 2:
1. hello, world
2. hello, world
3. hello, world
4. hello, world
https://ideone.com/TXci8L
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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