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  1. class A{
  2. public:
  3.     virtual bool operator<(const A & object) const = 0; // I assume you only care about B and C
  4. };
  5.  
  6. class C;
  7.  
  8. class B: public A{
  9. public:
  10.     virtual bool operator<(const A & object) const
  11.     {
  12.         // do a second bind, now that we know this is type B. Negate cause we
  13.         // are switching the operands.
  14.         return !object.operator<( (const B&)*this);
  15.     }
  16.     virtual bool operator<(const B & object) const
  17.     {
  18.         return true;
  19.     }
  20.     virtual bool operator<(const C & object) const
  21.     {
  22.         return true; // B is always < than C right?
  23.     }
  24. };
  25.  
  26. class C: public A{
  27. public:
  28.     virtual bool operator<(const A & object) const
  29.     {
  30.         // do a second bind, now that we know this is type C. Negate cause we
  31.         // are switching the operands.
  32.         return !object.operator<( (const C&)*this);
  33.     }
  34.     virtual bool operator<(const B & object) const
  35.     {
  36.         return false; // C is always > then B right?
  37.     }
  38.     virtual bool operator<(const C & object) const
  39.     {
  40.         return true;
  41.     }
  42. };
  43.  
  44. int main() {
  45.    A* a1 = new B();
  46.    A* a2 = new C();
  47.    bool r = *a1 < *a2;
  48. }
Runtime error #stdin #stdout 0s 11120KB
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https://ideone.com/LgFlvJ
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
secret

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