最基本的单链表C++

// 单链表.cpp -- 最基本的单链表C++ // Singly-linked list node template <class Elem> class Link { public: Elem element; // value for this node Link *next; // pointer to next node in list Link(const Elem& elemval, Link* nextval = NULL) { element = elemval; next = nextval;} Link (Link* nextval = NULL) { next = nextval;} }; // Linked list implementation template <class Elem> class LList: public Link<Elem> { private: Link <Elem>* head; // Pointer to list header Link <Elem>* tail; // Pointer to last Elem in list Link <Elem>* fence; // Last element on left side int leftcnt; // Size of left partition int rightcnt; // Size of right partition void init() // Intialization routine { fence = tail = head = new Link <Elem>; leftcnt = rightcnt = 0; } void removeall() // return nodes to free store { while(head != NULL) { fence = head; head = head -> next; delete fence; } } public: LList(int size = DefaultListSize) { init();} ~LList() {removeall();} // Destructor void clear() {removeall(); init();} bool insert(const Elem&); bool append(const elem&); bool remove(Elem&); void setStart() { fence = head; rightcnt += leftcnt; leftcnt = 0; } void setEnd() { fence = tail; leftcnt += rightcnt; rightcnt = 0;} void prev(); void next(); { if (fence != tail) // don't move fence if right empty { fence = fence -> next; rightcnt--; leftcnt++; } } int leftLength()const {return leftcnt;} int rightLength()const {return rightcnt;} bool setPos(int pos); bool getValue(Elem& it) const { if {rightLength() == 0) return false; // 当带了表结头，要先指向下一个元素取值。 // 如果带了表结头后，取值不是还是0,1,2,3...所以就要看具体的功能来写 it = fence -> next -> element; return true; } void print() const; }; template <class Elem> // Insert at front of right partition bool LList <Elem>::insert(const Elem& item) { fence -> next = new Link <Elem> (item, fence -> next); if (tail == fence) tail = fence -> next; // new tail rightcnt++; return true; } template <class Elem> // Append Elem to end of the list bool LList <Elem>::append(const Elem& item) { tail = tail -> next = new Link<Elem>(item, NULL); rightcnt++; return true; } // Remove and return first Elem in right partition template <class Elem> bool LList<Elem>::remove(Elem& it) { if (fence -> next == NULL) return false; // Empty right it = fence -> next -> element; // Remember value Link<Elem>* ltemp = fence -> next; // Remember link node fence -> next = ltemp -> next; // Remove from list if (tail == ltemp) tail = fence; // Reset tail delete ltemp; rightcnt--; return true; } // Move fence one step left; no change if left is empty template <class Elem> void LList<Elem>::setPos(int pos) { if ((pos < 0) || (pos > rightcnt + leftcnt)) return false; fence = head; for (int i = 0; i < pos; i++) fence = fence -> next; return true; } // Set the size of left partition to pos template <class Elem> bool LList<Elem>::setPos(int pos) { if ((pos < 0) || (pos > rightcnt + leftcnt)) return false; fence = head; for(int = 0; i < pos; i++) fence = fence -> next; return true; } template <class elem> void LList<Elem>::print() const { Link<Elem>* temp = head; cout << " < "; while(temp != fence) { cout << temp -> next -> element << " "; temp = temp -> next; } cout << " | "; while(temp -> next != NULL) { cout << temp -> next -> element << " "; temp = temp -> next; } cout << ">\n"; }