双向链表的插入操作_pta双链表插入操作。 #include using namespace std

#include <iostream>
using namespace std;

typedef struct LNode{
	int data;
	struct LNode *pre,*next;
}Node, *LinkList;

void Init_Linklist(LinkList &s){
	s = new Node;
	s->next = s->pre = NULL;
}

void create_LinkList(LinkList &s,int n){
	Node *p,*r;
	r = s;
	
	for(int i=0;i<n;i++){
		p = new Node;
		p->data = i+1;
		p->next=p->pre=NULL;
		
		r->next = p;
		p->pre = r;
		r = p;
	}
}

int insert_Node(LinkList &s,int n,int elem){
	
	Node *p = s;
	
	int i=1;
	while(p && i<n){
		p = p->next;
		i++;
	} 
	
	if(!p)
		return -1;
	
	Node *q = new Node;
	q->data = elem;
	q->pre = q->next = NULL;
	
	if(!p->next)
	{
		p->next = q;
		q->pre = p;
	}
	else{
		q->pre = p;
		q->next = p->next;
		p->next->pre = q;
		p->next = q;
	}

	
	
}

void show(LinkList s){
	Node *p = s->next;
	while(p){
		cout<<p->data<<" ";
		p = p->next;
	}
}

int main(){
	
	LinkList s;
	Init_Linklist(s);
	create_LinkList(s,5);
	insert_Node(s,6,10);
	show(s);
	return 0;
}
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