雙鏈表的建立以及插入，刪除操作



//雙鏈表
#include<iostream>
#include<string>
#include<stdio.h>
#include<stdlib.h>

using namespace std;

typedef struct student
{
	int data;
	struct student *next;
	struct student *prior;
}node;

node *creatlist()
{
	node *head, *p, *q;
	int x;
	head = (node*)malloc(sizeof(node));
	head->next = NULL;
	head->prior = NULL;
	//p = head->next;   頭插入法要用的；
	p = head;
	cout << "請輸入數據，以ctrl+z表示結束" << endl;
	//這是頭插入法；
	/*while (cin >> x)
	{
		q = (node*)malloc(sizeof(node));
		q->data = x;
		q->prior = head;
		q->next = p;
		head->next = q;
		
		p = q;
	}*/
	//這是尾插入法；輸出順序和頭插入不一樣；
	while (cin >> x)
	{
		q = (node*)malloc(sizeof(node));
		q->data = x;
		q->next = p->next;
		q->prior = p;
		p->next = q;
		p = q;
	}
	return(head);
}

void printlist(node *head)
{
	node *p;
	p = head->next;
	cout << "當前雙鏈表數據爲：" << endl;
	while (p != NULL)
	{
		cout << p->data << endl;
		p = p->next;
	}
	
}

//插入；
void insert(node *r, int x)
{
	node *p;
	p = (node*)malloc(sizeof(node));
	p->data = x;
	p->next = r->next;
	p->prior = r;
	r->next->prior = p;
	r->next = p;
}

//刪除；
void deletelist(node *head, int x)
{
	node *p, *q;
	q = head;
	p = head->next;
	while (p != NULL && p->data != x)
	{
		q = p;
		p = p->next;
	}
	if (p == NULL)
		cout << "該鏈表沒有這個數值" << endl;
	else {
		q->next = p->next;
		p->next->prior = q;
		free(p);
	}

}


int main()
{
	node *head;
	head = creatlist();
	insert(head, 88);
	deletelist(head, 5);
	printlist(head);
	system("pause");
	return 0;
}