C++ 单向链表

前言

最近终于闲下来了，把之前写的单向链表代码总结上传一下。

头文件

//声明头节点
struct Node {
	int val;
	Node* pNext;
	Node(int val) {
		this->val = val;
		this->pNext = NULL;
	}
};

//声明链表类
class List {
public:
	//创建链表
	Node* buildList(int arr[], int n);
	//打印链表
	void print(Node* head);
	
	//查
	bool checkNode(Node* head, int val);
	//改
	void changeNode(Node* head, int val, int des);
	//增
	Node* addNode(Node* head, int val , int addVal);
	//删
	Node* deleteNode(Node* head, int val);
	
	//删除链表
	void deleteList(Node* head);
};

cpp文件

#include"list.h"

//创建链表
Node* List::buildList(int arr[], int n) {
	//声明头节点和尾节点
	Node* head = NULL;
	Node* tail = NULL;

	//从数组中逐个取出元素创建节点
	for (int i = 0; i < n; i++) {
		Node *temp = (Node*)malloc(sizeof(Node));  //为新节点申请空间
		temp->val = arr[i];
		temp->pNext = NULL;
		if (head == NULL) {  //如果是链表的头节点
			head = temp;
			tail = temp;
		}
		else {  //如果不是的话加入到链表的后面，并把新的节点当作尾节点
			tail->pNext = temp;
			tail = temp;
		}
	}
	return head;  //返回头节点
}

//打印链表
void List::print(Node* head) {
	while (head) {
		cout << head->val << endl;
		head = head->pNext;
	}
}

//查找节点
bool List::checkNode(Node* head, int val) {
	Node* tmp = head;
	while (tmp) {
		if (tmp->val != val) {
			tmp = tmp->pNext;
		}
		else return true;
	}
	return false;
}

//更改节点
void List::changeNode(Node* head, int val, int des) {
	Node* tmp = head;
	while (tmp) {
		if (tmp->val == val) {
			tmp->val = des;
			return;
		}
		else tmp = tmp->pNext;
	}
}

//增加节点，非递归方法需要两个指针
Node* List::addNode(Node* head, int val, int addVal) {
	Node* tmp1 = head;
	Node* tmp2 = tmp1;
	Node* des = (Node*)malloc(sizeof(Node));
	des->val = addVal;
	des->pNext = NULL;

	if (head->val == val) {
		des->pNext = head;
		head = des;
		return head;
	}
	while (tmp1) {
		if (tmp1->val == val) {
			tmp2->pNext = des;
			des->pNext = tmp1;
			return head;
		}
		else {
			tmp2 = tmp1;
			tmp1 = tmp1->pNext;
		}
	}
	return head;
}

//删除节点
Node* List::deleteNode(Node* head, int val) {
	Node* cur = head;
	if (head->val == val) {
		head = head->pNext;
	}
	while (cur->pNext) {
		if (cur->pNext->val== val) {
			Node* tmp = cur->pNext;
			cur->pNext = cur->pNext->pNext;
			delete tmp;
			return head;
		}
		cur = cur->pNext;
	}
	return head;
}

//删除链表，从头到尾逐个删除并释放空间
void List::deleteList(Node* head) {
	Node* tmp = head;
	while (head) {
		tmp = head->pNext;
		delete head;
		head = tmp;
	}
}