实验二双链表

一、实验目的

巩固线性表的数据结构的存储方法和相关操作，学会针对具体应用，使用线性表的相关知识来解决具体问题。

二、实验内容

建立一个由n个学生成绩的顺序表，n的大小由自己确定，每一个学生的成绩信息由自己确定，实现数据的对表进行插入、删除、查找等操作。分别输出结果。

源代码为：

#include<iostream>  using namespace std;    template <typename T>  class  Node  {  public:      T data;      Node<T> *prior;      Node<T> *next;  };    template <typename T>  class DLL {  public:      DLL();      DLL(T score[], int n);  //有参构造函数      ~DLL();  //析构函数      int Length(); //返回单链表长度      void insert(int i, T x); //插入操作，在位置i插入元素      T get(int i);  //按位查找      int locate(T x);  //按值查找      T Delete(int i);  //删除操作      void print();  //遍历操作  private:      Node<T> *first;  //双链表的头指针      int length;   //链的长度计数  };    template <typename T>  DLL<T>::DLL(T score[], int n)  {      length=0;      first = new Node<T>;      first->next = NULL;      first->prior = NULL;      for (int i = 0; i<n; i++)      {          Node<T> *s = new Node<T>;          s->data = score[i];          s->next = first->next;           first->next = s;      }  }    template <typename T>  DLL<T>::~DLL()  {      while (first->next!=first->prior)      {          //临时指针，存储即将释放的节点的指针          Node<T> *temp = first;          //脱链          first->prior->next = first->next;          first->next -> prior = first->prior;          //头指针后移          first = first->next;          //释放内存          delete temp;      }      delete first;  }    template<typename T>  int DLL<T>::Length()  {      Node<T> *p; int count;      p=first->next;        count=0;        while(p!=NULL)      {            p=p->next;            count++;         }        return length;  }    template <typename T>  void DLL<T>::insert(int i,T x)  {      Node<T>*p,*s;int count;        p=first;         count=0;        while(p!=NULL&&count<i-1)        {            p=p->next;            count++;                 }         if(p==NULL) throw"位置";         else       {           s=new Node<T>;           s->data=x;           s->next=p->next;           p->next=s;         }  }    template <typename T>  T DLL<T>::get(int i)  {      Node<T> *p;int count; count = 1;      p = first->next;       while (p != NULL&&count<i)      {          p = p->next; count++;      }      if (p == NULL)throw"位置非法";      else return p->data;  }    template <typename T>  int DLL<T>::locate(T x)  {      Node<T> *p; int count;      p = first->next; count = 1;      while (p!= NULL)      {          if (p->data == x) return count;          p = p->next;          count++;      }      return 0;  }    template <typename T>  T DLL<T>::Delete(int i)  {      Node<T> *p,*q;      p = first->next; int count, x; count = 1;      while (p != NULL&&count<i-1)      {          p = p->next; count++;      }      if (p == NULL || p->next == NULL) throw"位置非法";      else      {            q = p->next;            x=q->data;            if (p->next != NULL)          {                if(q->next!=NULL)            q->next->prior = p;              else              {                  p->next=NULL;                  p->next = q->next;                  delete q;                  q = NULL;                  return x;              }          }          p->next = q->next;          delete q;            q = NULL;            return x;      }  }    template <typename T>  void DLL<T>::print()  {      Node<T> *p;      p = first->next;      while (p->next != NULL)      {          cout << p->data << " ";          p = p->next;      }      cout << p->data << endl;  }    void main()  {      float score[8] = { 69,85,95,74,55,64,100,87 };      DLL<float>student(score, 8);      cout << "     学生数据结构成绩" << endl;      student.print();      cout << endl << endl << "在位置5插入成绩68，插入后结果如下：" << endl;      student.insert(5,68);      student.print();      cout << endl << endl << "在位置2删除成绩为：" << student.Delete(2) <<" , "<< "删除后结果如下:" << endl;      student.print();      cout << endl << endl << "位置4的成绩为：" << student.get(4) << endl;      cout << endl << endl << "成绩74所在位置为：" << student.locate(74) << endl;  }