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  1. #include <iostream>
  2.  
  3. typedef void(*ISSFUNC)(void*);
  4.  
  5. struct AInst
  6. {
  7.     void* data;
  8.     ISSFUNC func;
  9. };
  10.  
  11. AInst* mInst;
  12.  
  13. void saveAInst(void* inst, ISSFUNC func)
  14. {
  15.     mInst = new AInst();
  16.     mInst->data = inst;
  17.     mInst->func = func;
  18. }
  19.  
  20. void issueInst()
  21. {
  22.     mInst->func(mInst->data);
  23.     delete mInst;
  24. }
  25.  
  26. class AHandler
  27. {
  28. public:
  29.     virtual void print() = 0;
  30. };
  31.  
  32. class A
  33. {
  34. private:
  35.     AHandler* mHandler;
  36.  
  37.     static void funct(void* data)
  38.     {
  39.         A* a = reinterpret_cast<A*>(data);
  40.         a->mHandler->print();
  41.     }
  42. public:
  43.     A(AHandler* handler = nullptr) : mHandler(handler)
  44.     {
  45.         saveAInst(this, &funct);
  46.     }
  47. };
  48.  
  49. class AHandlerImpl1 : public AHandler
  50. {
  51. public:
  52.     virtual void print() override
  53.     {
  54.         std::cout << "Implementation 1\n";
  55.     }
  56. };
  57.  
  58. class AHandlerImpl2 : public AHandler
  59. {
  60. public:
  61.     virtual void print() override
  62.     {
  63.         std::cout << "Implementation 2\n";
  64.     }
  65. };
  66.  
  67. int main()
  68. {
  69.     AHandlerImpl1 impl1;
  70.     AHandlerImpl2 impl2;
  71.  
  72.     A a1(&impl1);
  73.  
  74.     issueInst();
  75.  
  76.     A a2(&impl2);
  77.  
  78.     issueInst();
  79.  
  80.     return 0;
  81. }
  82.  
Success #stdin #stdout 0s 3228KB
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stdin
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Standard input is empty
stdout
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Implementation 1
Implementation 2
https://ideone.com/l2GkBc
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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