c++ 链表类简易模板

#include<iostream>
using namespace std;

int n,a,v1,v2;

template<typename T>
class LinkList{
private:
    struct Node{
        T data;
        Node *next;
        Node(T val): data(val), next(nullptr){}
    };

    Node *head;

public:
    LinkList(): head(nullptr){}
    ~LinkList(){
        while(head){
            Node *temp=head;
            head=head->next;
            delete temp;
        }
    }

    void pushFront(T val) {
        Node* newNode = new Node(val);
        newNode->next = head;
        head = newNode;
    }

    void pushBack(T val){
        Node *newNode=new Node(val);
        if(!head){
            head=newNode;
            return;
        }
        Node *current=head;
        while(current->next){
            current=current->next;
        }
        current->next=newNode;
    }

    void insertAfter(T targetVal, T newVal){
        Node *current = head;
        while(current){
            if(current->data==targetVal){
                Node *newNode= new Node(newVal);
                newNode->next=current->next;
                current->next=newNode;
                return;
            }
            current = current->next;
        }
        pushBack(newVal);
    }

    void checkAfter(T val){
        Node *current=head;
        while(current){
            if(current->data==val){
                if(current->next){
                    cout << current->next->data <<endl;
                } else {
                    cout << "0" << endl;
                }
                return;
            }
            current = current->next;
        }
        cout << "Value " << val << " not found in list" << endl;
    }

    void removeAfter(T val) {
        if (!head) return;  // 空链表
        Node* current = head;
        while (current) {
            if (current->data == val) {
                Node* temp = current->next;
                current->next = current->next->next;
                delete temp;
                return;
            }
            current = current->next;
        }
    }

    void print() {
        Node* current = head;
        while(current) {
            cout << current->data << " -> ";
            current = current->next;
        }
        cout << "nullptr" << endl;
    }
};

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    LinkList<int> mylist;
    mylist.pushFront(1);
    cin>> n;
    for(int i=1;i<=n;i++){
        cin >> a;
        if(a==1){
            cin >> v1 >> v2;
            mylist.insertAfter(v1,v2);
        }else if(a==2){
            cin >> v1;
            mylist.checkAfter(v1);
        }else{
            cin >> v1;
            mylist.removeAfter(v1);
        }
    }
}