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  1. #include <iostream>
  2.  
  3. struct Base
  4. {
  5.     void beginEvent(int a)
  6.     {
  7.         impl(a, &Base::onBeginEvent, &Base::onBeginEvent);
  8.     }
  9.  
  10.     void endEvent(int a)
  11.     {
  12.         impl(a, &Base::onEndEvent, &Base::onEndEvent);
  13.     }
  14.  
  15.     void impl(int a, void (Base::*func1)(int), void (Base::*func2)(int, int))
  16.     {
  17.         (this->*func1)(a);
  18.         (this->*func2)(a, -a);
  19.     }
  20.  
  21.     virtual void onBeginEvent(int a){}
  22.     virtual void onBeginEvent(int a, int negativeA){}
  23.     virtual void onEndEvent(int a){}
  24.     virtual void onEndEvent(int a, int negativeA){}
  25. };
  26.  
  27. struct Derived : public Base
  28. {
  29.     void onBeginEvent(int a) { std::cout << a << "\n"; }
  30.     void onEndEvent(int a, int b) { std::cout << a << "==(-(" << b << "))\n"; }
  31. };
  32.  
  33. int main() 
  34. {
  35.     Derived d;
  36.  
  37.     d.beginEvent(3);
  38.     d.endEvent(9);
  39.  
  40. 	return 0;
  41. }
Success #stdin #stdout 0.01s 2680KB
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stdin
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Standard input is empty
stdout
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3
9==(-(-9))
https://ideone.com/3WkSsu
language:
C++ (gcc 8.3)
created:
12 years ago
visibility:
public

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