#include <iostream>
using namespace std;

struct Node {
    int data;
    Node* next;
};

Node* head = nullptr;
void insertNode(int data)
{
    Node* newNode = new Node();
    newNode->data = data;
    newNode->next = nullptr;

    //head沒有東西
    if (head == nullptr) {
        head = newNode;
        return; 
    }
    //head有東西
    Node* now = head;
    //找到 ->next 是空的接上去
    while (now->next!=nullptr) {
        now = now->next;
    }
    now->next = newNode;
}
void deleteNode(int data)
{
    if (head==nullptr) return; 
    //找到要刪除的節點
    Node* to_delete = head;
    Node* prev = nullptr;
    while (to_delete->data != data) {
        prev = to_delete;
        to_delete = to_delete->next;
    }
    if (to_delete!=nullptr) {
        if(prev == nullptr) head = to_delete->next;
        else prev->next = to_delete->next;

        delete to_delete;
    }   
}
void printList()
{
    Node* now = head;
    while (now!=nullptr) {
        cout << now->data << " ";
        now = now-> next;
    }
    cout << endl;
}
int main() {
    insertNode(1);
    insertNode(2);
    insertNode(3);
    insertNode(4);
    insertNode(5);
    printList();
    // 刪除首節點
    deleteNode(1);
    printList();
    // 刪除中間
    deleteNode(3);
    printList();
    
    return 0;
}
c