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  1. //#include <iterator>
  2. #include <cstdio>
  3.  
  4. struct A{
  5. 	struct iterator/*: public std::iterator<std::input_iterator_tag, int>*/{
  6. 		A& up;
  7. 		int i;
  8. 		iterator(A& up,int i):up(up),i(i){}
  9. 		bool operator!=(iterator const& b) {
  10. 			return i != b.i;
  11. 		}
  12. 		int operator*() {
  13. 			return up.b;
  14. 		}
  15. 		iterator& operator++(){
  16. 			int r=up.a+up.b;
  17. 			up.b=up.a;
  18. 			up.a=r;
  19. 			i-=1;
  20. 			return *this;
  21. 		}
  22. 	};
  23. 	int n,a=1,b=1;
  24. 	A(int n):n(n){}
  25. 	iterator begin(){
  26. 		return iterator(*this,n);
  27. 	}
  28. 	iterator end(){
  29. 		return iterator(*this,0);
  30. 	}
  31. };
  32.  
  33. int main()
  34. {
  35. 	for (auto x:A(10)){
  36. 		printf("%-3d",x);
  37. 	}
  38. }
  39.  
Success #stdin #stdout 0s 5304KB
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1  1  2  3  5  8  13 21 34 55
https://ideone.com/OFnrw7
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
public

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