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  1. #include <iostream>
  2. #include <functional>
  3.  
  4.  
  5. template<typename T, typename R, typename ... Args>
  6. std::function<R (Args...)> MakeDelegate(T *obj, R (T::*ptr)(Args ...))
  7. {
  8.    return [obj, ptr](Args ... args)-> R {return (obj->*ptr)(args...);};
  9. }
  10.  
  11. template<typename T, typename R, typename ... Args>
  12. auto DelegateType(R (T::*ptr)(Args ...))->decltype(MakeDelegate<T>(nullptr, ptr));
  13.  
  14. class A 
  15. {
  16. public:
  17. void f1(int arg){std::cout << "A::f1(" << arg << ")" << std::endl;}; 
  18. void f2(int arg1, int arg2){std::cout << "A::f2(" << arg1 << ", " << arg2 << ")" << std::endl;}; 
  19. };
  20.  
  21. A a;
  22.  
  23. class B
  24. {
  25. public:
  26.    B() : m_d1(MakeDelegate(&a, &A::f1)), m_d2(MakeDelegate(&a, &A::f2))
  27.    {
  28.  
  29.    }
  30.  
  31.    void test()
  32.    {
  33.       m_d1(40);
  34.       m_d2(50, 60);
  35.    }
  36. private:
  37.    decltype(DelegateType(&A::f1)) m_d1;
  38.    decltype(DelegateType(&A::f2)) m_d2;
  39. };
  40.  
  41. auto Delegate1 = MakeDelegate(&a, &A::f1);
  42. auto Delegate2 = MakeDelegate(&a, &A::f2);
  43.  
  44. int main()
  45. {
  46.    Delegate1(10);
  47.    Delegate2(20, 30);
  48.  
  49.    B b;
  50.    b.test();
  51.  
  52.    return 0;
  53. }
  54.  
Success #stdin #stdout 0s 3032KB
comments (?)
stdin
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Standard input is empty
stdout
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A::f1(10)
A::f2(20, 30)
A::f1(40)
A::f2(50, 60)
https://ideone.com/O9OsZq
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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