[数据结构]双向链表及其基本操作 原创

#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);
}