从零构建链表

        Node* Head=new Node; //头节点 不存储数据

        Head->next = NULL;

        Node* pre = Head; //指向下一个节点的过渡值，本质就是保留住head这个虚拟头节点，不丢失它

#include<iostream>

using namespace std;

struct Node {

        int val;

        Node* next;

};

//创建

Node* creatlist(int n) {

        Node* Head=new Node; //头节点 不存储数据

        Head->next = NULL;

        Node* pre = Head; //指向下一个节点的过渡值

        cout << "请依次输入" << n << "个链表的值:";

        for (int i = 0;i < n;i++) {

                Node* temp = new Node;

                cin >> temp->val;

                pre->next = temp;

                pre = temp;

                temp->next = NULL;        

        }

        return Head;

}

//显示

void display(Node* head) {

        Node* temp=head->next;

        int e;

        cout << "该链表的遍历依次为：";

        while (temp!=NULL) {

                e = temp->val;

                cout << e << " ";

                temp = temp->next;

        }

        cout << "\n";

}

int main() {

        int nums;

        cout << "请输入链表的长度:";

        cin >> nums;

        Node* head = creatlist(nums);

        display(head);

        return 0;

}