數據結構：線性表之雙鏈表

雙鏈表與單鏈表對比，多了一個指向前驅的指針，其他類同

#include<iostream>

using namespace std;

typedef struct LNode
{
    int data;
    struct LNode *next,*prior;
}LNode,*Link;


void Init_Link(Link &L)
{
    L = new LNode;
    L->next = NULL;
    L->prior = NULL;
}

void Insert_Link(Link &L,int i,int e)
{
    if(i < 1)
        return;
    Link p;
    p = L;


    int j = 1;
    while(p && j < i)
    {
        p = p->next;
        j++;
    }

    LNode *s;
    s = new LNode;

    s->data = e;
    if(p->next != NULL)
        p->next->prior = s;
    s->next = p->next;

    s->prior = p;
    p->next = s;

}

void Traverse(Link L)
{
    Link p;
    p = L->next;
    while(p)
    {
        cout << p->data << " ";
        p = p->next;
    }
}
int searchElemPrior(Link L,int i)
{
    if(i == 1)
        return 0;
    Link p;
    p = L->next;
    int j = 1;
    while(p && j < i)
    {
        p = p->next;
        j++;
    }
    return p->prior->data;
}
int main()
{
    Link L;
    Init_Link(L);
    for(int i = 1; i < 5; i++)
    {
        Insert_Link(L,i,i);
    }
    Insert_Link(L,3,5);
    Traverse(L);
    cout <<endl;
    int a = searchElemPrior(L,5);
    cout << a ;
    return 0;
}