链表头部插入和尾部插入

小鱼儿 2021-12-15 18:47 246阅读 0赞

## 链表头部插入和尾部插入 ##

**头部插入**

void NodeList::addToHead()
    {
    	for (int i = 0; i < arrrlens; i++)
    	{
    		int node = arr_1[i];
    		Node* p = new Node(node, NULL);
    		if (i == 0) {
    			head = p;
    		}
    		else {
    			p->next = head;
    			head = p;
    		}
    	}
    }

**尾部插入**

void NodeList::addToTail()
    { 
    	Node *fp = head;
    	for (int i = 0; i < arrrlens; i++)
    	{
    		int node = arr_2[i];
    		Node* p = new Node(node, NULL);
    		fp->next = p;
    		fp = p;
    	}
    	//删除头部为空节点
    	Node* newHead = head->next;
    	delete head;
    	head = newHead;
    }

**源码**

#include<stdio.h>
    #include<iostream>
    using namespace std;
    //测试数据
    const int arrrlens = 5;
    int arr_1[arrrlens] = { 9, 7, 5, 3, 1 };
    int arr_2[arrrlens] = { 0, 2, 4, 6, 8 };
    class Node {
    public:
    	//构造函数，创建一个节点
    	Node(int el = NULL, Node* ptr = NULL) {
    		infor = el;
    		next = ptr;
    	}
    	int infor;
    	Node* next;
    };
    class NodeList {
    public:
    	NodeList() {
    		head = new Node();
    	}
    	~NodeList() {
    		delete head;
    	}
    	//节点插入头部
    	void printList();
    	void addToHead();
    	void addToTail();
    	Node* getHead();
    	//Node* mergeTwoOrderLists(NodeList*, NodeList*);
    	
    private:
    	Node* head;
    };
    //头部插入法链表顺序与输入数据顺序相反
    Node* NodeList::getHead()
    {
    	return head;
    }
    void NodeList::addToHead()
    {
    	for (int i = 0; i < arrrlens; i++)
    	{
    		int node = arr_1[i];
    		Node* p = new Node(node, NULL);
    		if (i == 0) {
    			head = p;
    		}
    		else {
    			p->next = head;
    			head = p;
    		}
    	}
    }
    void NodeList::addToTail()
    { 
    	Node *fp = head;
    	for (int i = 0; i < arrrlens; i++)
    	{
    		int node = arr_2[i];
    		Node* p = new Node(node, NULL);
    		fp->next = p;
    		fp = p;
    	}
    	//删除头部为空节点
    	Node* newHead = head->next;
    	delete head;
    	head = newHead;
    }
    
    void NodeList::printList()
    {
    	Node* p = head;
    	while (p != NULL)
    	{
    		printf("%d ", p->infor);
    		p = p->next;
    	}
    	printf("\n");
    }
    int main()
    {
    	NodeList nlist_1, nlist_2;
    	nlist_1.addToHead();
    	nlist_2.addToTail();
    	nlist_1.printList();
    	nlist_2.printList();
    }