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  1. #include <iostream>
  2. #include <vector>
  3. #include <list>
  4. using namespace std;
  5.  
  6. // demo class 
  7. class Item {
  8. 	int i; 
  9. public: 
  10.     Item(int v=0) : i(v) {}
  11.     friend ostream& operator<< (ostream& os, const Item &item); 
  12. };
  13. ostream& operator<< (ostream& os, const Item &item) {
  14. 	return (os << item.i); 
  15. } 
  16.  
  17. template <template <typename...> class C, class T>
  18. class Adder {
  19. public:
  20. 	void operator() (C<T>& a, const T& element);  
  21. };
  22.  
  23. template <class T>
  24. class Adder<vector, T> {
  25. public: 
  26.    void operator() (vector<T>& a, const T& element) {
  27.    	   a.push_back(element); 
  28.    } 
  29. };
  30.  
  31. template <class T>
  32. class Adder<list, T> {
  33. public: 
  34.    void operator() (list<T>& a, const T& element) {
  35.    	   a.push_front(element); 
  36.    } 
  37. };
  38.  
  39. template <template <typename...> class C, class T>
  40. class SmartContainer {
  41. 	C<T> mycontainer; 
  42. 	Adder<C,T> a; 
  43. public:  
  44. 	void add (const T& element) { a(mycontainer, element); } 
  45. 	int get_number_of_elements() { return mycontainer.size(); } 
  46. 	void print() { for (auto &x:mycontainer) 
  47. 	                   cout << x<<endl;  
  48. 	               cout<<endl; }
  49. };
  50.  
  51.  
  52. int main() {
  53. 	Item item1(10), item2(20); 
  54.  
  55. 	SmartContainer<vector, Item> c1; 
  56. 	c1.add(item1);
  57. 	c1.add(item2);
  58. 	cout<< "Size: "<<c1.get_number_of_elements()<<endl; 
  59. 	c1.print(); 
  60.  
  61. 	SmartContainer<list, Item> c2; 
  62. 	c2.add(item1);
  63. 	c2.add(item2);
  64. 	cout<< "Size: "<<c2.get_number_of_elements()<<endl; 
  65. 	c2.print(); 
  66.  
  67. 	return 0;
  68. }
  69.  
  70.  
Success #stdin #stdout 0s 3472KB
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Size: 2
10
20

Size: 2
20
10
https://ideone.com/f5LSv5
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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