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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. template<typename T>
  5. void println(T data) {
  6. 	cout << data << endl;
  7. }
  8.  
  9. template<typename T>
  10. class List {
  11. public:
  12. 	class Item {
  13. 	protected:
  14. 		T data;
  15. 		Item* prev;
  16. 		Item* next;
  17. 	public:
  18. 		Item(T data, Item* prev, Item* next) {
  19. 			this->data = data;
  20. 			this->prev = prev;
  21. 			this->next = next;
  22. 		}
  23. 		T* getData() {
  24. 			return &data;
  25. 		}
  26. 		Item* getNext() {
  27. 			return next;
  28. 		}
  29. 		Item* getPrev() {
  30. 			return prev;
  31. 		}
  32. 	};
  33. private:
  34. 	class ExtendedItem : Item {
  35. 	public:
  36. 		void setPrev(Item* prev) {
  37. 			this->prev = prev;
  38. 		}
  39. 		void setNext(Item* next) {
  40. 			this->next = next;
  41. 		}
  42. 		void removeSelf() {
  43. 			if (next)
  44. 				((ExtendedItem*)next)->setPrev(prev);
  45. 			if (prev)
  46. 				((ExtendedItem*)prev)->setNext(next);
  47. 		}
  48. 	};
  49. 	Item* first;
  50. 	Item* last;
  51. public:
  52. 	List() {
  53. 		println("Default constructor called");
  54. 		first = NULL;
  55. 		last = NULL;
  56. 	}
  57. 	List(List<T>& other) {
  58. 		println("Copy constructor called");
  59. 		first = NULL;
  60. 		last = NULL;
  61. 		for (Item* cur = other.getFront(); cur != NULL; cur = cur->getNext()) {
  62. 			pushBack(*cur->getData());
  63. 		}
  64. 	}
  65. 	~List() {
  66. 		println("Destructor called");
  67. 		while (first != NULL) {
  68. 			Item* next = first->getNext();
  69. 			// ((ExtendedItem*)first)->removeSelf();
  70. 			delete first;
  71. 			first = next;
  72. 		}
  73. 	}
  74. 	Item* pushFront(T data) {
  75. 		Item* newOne = new Item(data, NULL, first);
  76. 		if (first != NULL)
  77. 			((ExtendedItem*)first)->setPrev(newOne);
  78. 		first = newOne;
  79. 		if (last == NULL)
  80. 			last = newOne;
  81. 		return newOne;
  82. 	}
  83. 	Item* pushBack(T data) {
  84. 		Item* newOne = new Item(data, last, NULL);
  85. 		if (last != NULL)
  86. 			((ExtendedItem*)last)->setNext(newOne);
  87. 		last = newOne;
  88. 		if (first == NULL)
  89. 			first = newOne;
  90. 		return newOne;
  91. 	}
  92. 	Item* getFront() {
  93. 		return first;
  94. 	}
  95. 	Item* getBack() {
  96. 		return last;
  97. 	}
  98. 	void remove(Item* element) {
  99. 		if (element == NULL)
  100. 			return;
  101. 		((ExtendedItem*)element)->removeSelf();
  102. 		if (element == first)
  103. 			first = first->getNext();
  104. 		if (element == last)
  105. 			last = last->getPrev();
  106. 		delete element;
  107. 	}
  108. 	template <typename C, bool Pred(T*, C)>
  109. 	Item* find(C context) {
  110. 		for (Item* cur = first; cur != NULL; cur = cur->getNext())
  111. 			if (Pred(cur->getData(), context))
  112. 				return cur;
  113. 		return NULL;
  114. 	}
  115. };
  116.  
  117. List<size_t>& newList(size_t a) {
  118. 	List<size_t> result;
  119. 	result.pushBack(a);
  120. 	return result;
  121. }
  122.  
  123. int main() {
  124. 	List<size_t> a = newList(1);
  125. 	for (List<size_t>::Item* cur = a.getFront(); cur != NULL; cur = cur->getNext())
  126. 		println(*cur->getData());
  127. 	return 0;
  128. }
Runtime error #stdin #stdout 0s 15240KB
comments (?)
stdin
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Standard input is empty
stdout
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Default constructor called
Destructor called
Copy constructor called
https://ideone.com/7qm0Mo
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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