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  1.     #include <iostream>
  2.  
  3.     template<typename T>
  4.     class DCLL
  5.     {
  6.         // internal representation of a Node
  7.         struct Node
  8.         {
  9.             T        m_value;
  10.             Node*    m_next;
  11.             Node*    m_prev;
  12.  
  13.             inline Node(T value, Node* prev, Node* next)
  14.             {
  15.                 m_value = value;
  16.                 m_prev = prev;
  17.                 m_next = next;
  18.                 if (m_prev)
  19.                     m_prev->m_next = this;
  20.                 if (m_next)
  21.                     m_next->m_prev = this;
  22.             }
  23.         };
  24.  
  25.         Node* m_head;
  26.         Node* m_tail;
  27.  
  28.     public:
  29.         DCLL() : m_head(nullptr), m_tail(nullptr) {}
  30.  
  31.         void push_front(T val)
  32.         {
  33.             m_head = new Node(val, nullptr, m_head);
  34.             if (!m_tail)
  35.                 m_tail = m_head;
  36.         }
  37.  
  38.         void push_back(T val)
  39.         {
  40.             m_tail = new Node(val, m_tail, nullptr);
  41.             if (!m_head)
  42.                 m_head = m_tail;
  43.         }
  44.  
  45.         void walk() const {
  46.             for (Node* node = m_head; node != nullptr; node = node->m_next) {
  47.                 std::cout << node->m_value << ' ';
  48.             }
  49.             std::cout << '\n';
  50.         }
  51.     };
  52.  
  53.     int main() 
  54.     {
  55.         DCLL<int> ints;
  56.         ints.push_front(3);
  57.         ints.push_front(2);
  58.         ints.push_front(1);
  59.         ints.push_back(4);
  60.         ints.push_back(5);
  61.         ints.push_back(6);
  62.  
  63.         ints.walk();
  64.  
  65.         return 0;
  66.     }
Success #stdin #stdout 0s 3428KB
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https://ideone.com/nwlrbi
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
public

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