双向链表按位置插入时出问题,只有两个数据的时候,Length()函数在Insert函数里居然能达到3（所以判断条件里不得不-1)如果只2个或3个数据,Length（）函数在主函数里输出时正常.
不最主要还是按位置插入时，那段代码检查了几遍找不到哪里错了.
#include <iostream>
using namespace std;
template <class T>
class Double;

template <class T>
class DoubleNode
{
    friend Double<T>;
    private :
        T data;
        DoubleNode<T> *right,*left;
};

template <class T>
class Double
{
public:
    Double(){LeftEnd=RightEnd=0;}
    ~Double();
    int Length();
    bool Find(int k,T& x)const;
    int Serach(const T& x)const;
    Double<T>& Delete(int k,T& x);
    Double<T>& Insert(int k,const T& x);
    void Output(ostream& out) const;
private:
    DoubleNode<T> *LeftEnd,*RightEnd;

};

template <class T>
Double<T>::~Double()
{
    DoubleNode<T> *t;
    t=LeftEnd;
    while(t)
    {
        t=LeftEnd->right;
        delete LeftEnd;
        LeftEnd=t;
    }
}

template <class T>
Double<T>& Double<T>::Insert(int k,const T&x)
{
    DoubleNode<T> *t;
    t=new DoubleNode<T>;
    t->data=x;
    if(k==0)
    {
    t->right=0;
    t->left=0;
    LeftEnd=t;
    }
    if(k==1)
    {
        t->right=0;
        t->left=LeftEnd;
        LeftEnd->right=t;
        RightEnd=t;
    }
    if(k>1&&k==Length())
    {
        t->left=RightEnd;
        t->right=0;
        RightEnd->right=t;
        RightEnd=t;
    }
    if(k>1&&k<Length()-1) //按位置插入就这段代码处理，我是没找问题出在哪了
    {
        DoubleNode<T> *c;
        DoubleNode<T> *cr;
        c=LeftEnd;
        for(int i=0;i<k-1;i++)
            c=c->right;
        cr=c->right;
        t->left=c;
        t->right=cr;
        c->right=t;
        cr->left=t;
    }

    return *this;
}

template <class T>
void Double<T>::Output(ostream& out) const
{
    DoubleNode<T> *t;
    t=LeftEnd;
    if(!t->right&&!t->left)
        cout<<t->data<<" ";
    else
    {
        while(t->right)
        {
        cout<<t->data<<" ";
        t=t->right;
        }
        cout<<t->data<<" ";
    }
        cout<<endl;
}

template <class T>
int Double<T>::Length()
{
    int l=1;
    DoubleNode<T> *t;
    t=LeftEnd;
    if(!t->right&&!t->left) return l;
    else
    {
        while(t->right)
        {
            l++;
            t=t->right;
        }
        return l;
    }
}

template <class T>
ostream& operator<<(ostream&out,const Double<T>& x)
{
    x.Output(out);
    return out;
}


int main()
{
 Double<int> d;
 d.Insert(0,1).Insert(1,2).Insert(2,3).Insert(3,4).Insert(4,5).Insert(5,6);
 cout<<d;
 d.Insert(3,13); 按位置插入时出问题
 cout<<d;
 cout<<d.Length()<<endl;
 return 0;
}

[ 本帖最后由 mfkblue 于 2009-8-11 18:24 编辑 ]

template<class Type>
class DblinkNode
{
    public:
    DblinkNode<Type> * m_next;
    DblinkNode<Type> * m_prev;
    Type m_data;
 DblinkNode()
{
   m_next = 0;
   m_prev = 0;
   
}
   
    void InsertAffter(Type p_item)
{
    DblinkNode<Type> * newnode = new DblinNode<Type>;
    newnode->m_data = p_item;
    newnode->m_next = m_next;
   newnode ->m_prev = this;
   if(m_next != 0)
 m_next->m_next = newnode;
  
m_next = newnode;
}
};
写个简单的吧，

[ 本帖最后由 missiyou 于 2009-8-10 21:25 编辑 ]

InsertAffter 看你这函数应该是在链表的最后一个添加数据，这步我倒是处理完了，出问题的是链表的中间插入.

暂时搞定，写错了个判断条件