[数据结构]双向链表及其基本操作

#include <iostream>
#include <cstdio>

using namespace std;

typedef int Elem;
typedef int Status;

typedef struct DulList //我猜是 doubole list...
{
  /* data */
  Elem data;
  struct DulList *prior;
  struct DulList *next; // 前 后 指针
} DulList, *DulLinkList;

Status InitDulList(DulLinkList &L)
{
  L = new DulList;
  L->next = NULL;
  L->prior = NULL;

  return 1;
}

Status CreatDulList_H(DulLinkList &L, int num)
{
  L = new DulList;
  L->next = NULL;

  for (int i = 1; i <= num; i++)
  {
    DulList *p = new DulList;
    cin >> p->data;

    p->next = L->next;
    if (L->next) L->next->prior = p;
    L->next = p;
    p->prior = L;
  }

  return 1;
}

DulList* GetElemDulList(DulLinkList &L, int i) //这个真就 DulList* ...
{
  DulList *p = L;
  int j = 0;

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

  if (i<1 || j>i)
    ;//这个不该这么写 其实

  return p;
}

Status InsertDulList(DulLinkList &L, int i, Elem e)
{
  DulList *p = L;

  if (!(p = GetElemDulList(L, i))) //P的位置其实被改了 不会出现 插在头的情况
    return -1;

  DulList *s = new DulList;

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

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

  return 1;
}

Status DelDulList(DulLinkList &L, int i) //Delete
{
  DulList *p = L->next;
  if (!(p = GetElemDulList(L, i)))
    return -1;

  DulList *s = new DulList;

  p->prior->next = p->next;
  p->next->prior = p->prior; //前后跳着指 中间就空一格了

  return 1;
}

Status ShowDulList(DulLinkList &L) {

  DulList *p = L->next;

  while (p)
  {
    cout << p->data<<" ";
    p = p->next;
  }

  return 1;
}

int main()
{
  DulLinkList L;

  //1
  InitDulList(L);

  //1
  CreatDulList_H(L, 3);

  //1
  InsertDulList(L, 2, 1);

  //1
  ShowDulList(L);

  //1
  DelDulList(L, 2);

  //1
  ShowDulList(L);
}