无法确定未解决的外部错误来自何处

我正在创建的程序不断出现一个未解决的外部符号错误，我无法弄清楚我哪里出错了 .

即将出现的错误是：

错误LNK1120：1个未解析的外部

错误LNK2019：未解析的外部符号“public：__thiscall linkedList :: ~linkList（void）”（?? 1linkedList @@ QAE @ XZ）在函数“void cdecl`dynamic atexit析构函数为'list''（void）”中引用（？ ？ FLIST @@ YAXXZ）

任何帮助将不胜感激 .

source.cpp

#include <iostream>
#include <string>
#include "LList.h"
#include "vehicle.h"
#include "windows.h"
#include <iomanip>

using namespace std;

linkedList list;

int main()
{
    char menuSelect;

    do
    {
        menuSelect = NULL;
        cout << "Please press one of the following options:";
        cout << "\n=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-";
        cout << "\n1. List all vehicles";
        cout << "\n2. Add a vehicle (Car or Van)";
        cout << "\n3. Remove a vehicle";
        cout << "\n4. Book a car";
        cout << "\n5. Book a van";
        cout << "\n6. Display a vehicle's details";
        cout << "\n7. List all cars currently not rented";
        cout << "\n8. List all 5-door cars";
        cout << "\n9. List all Ford vans currently rented";
        cout << "\n0. Quit";
        cout << "\n=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-\n";
        cin >> menuSelect;

        void addNode();
        void deleteNode();
        void getVehicles();

    switch (menuSelect)
    {
    case '1':
        getVehicles();  //displays all vehicles in the list.  
        break;

    case '2':
        addNode();          //allows the user to add another vehicle.
        break;
    case '3':
        deleteNode();       //allows the user to delete a vehicle. 
        break;
    case '4':
                            //allows the user to book a car.
        break;              
    case '5':           
                            //allows the user to book a van.
        break;
    case '6':           
                            //allows the user to select a vehicle and show it's details.
        break;
    case '7':
                            //lists all the vehicles that are currently not rented.
        break;
    case '8':               //lists all cars that are 5 door. 
        break;

    case '9':               //lists all of the Ford vans that are currently rented. 
        break;

    case '0':
        system("pause");
        return 0;

        break;

    default: cout << "\n" << menuSelect << " is not a valid selection.";

        cout << endl;

    }

}
    while (menuSelect != 0);
    return 0;

}

void addNode()
{
        node* newNode = new node;
        cout << "Is it a car or van?: \n";
        cin >> newNode->make;

        cout << "\nEnter model: \n";
        cin >> newNode->model;

        cout << "\nEnter engine size: \n";
        cin >> newNode->engine;

        cout << "\nEnter registration number: \n ";
        cin >> newNode->registration;

        list.insertNode(newNode);

}

void deleteNode()
{
    char searchData;
        cout << "Enter the registration plate to be deleted: ";
        cin >> searchData;
    if (list.deleteNode(searchData))
        cout << "\nNode deleted. \n\n\n";

        cout << "\nThe registration plate is not in the list\n\n";
}

void getVehicles()
{
    string searchData;
    list.displayList();

}

LLIST.H

#include <string>
#include "vehicle.h"
#include "windows.h"
#include <iostream>


using namespace std;


struct node
{
    int registration;
    double engine;
    string model;
    string make;
    node* nextNode;
    int data;
};

class linkedList
{
private:
    node* head;

public:
    linkedList() { head = NULL; }
    void insertNode(node*);
    void searchNode(int);
    bool deleteNode(int deleteVehicle);
    void displayList();
    ~linkedList();

};

Llist.cpp

#include <iostream>
#include "windows.h"
#include <string>
#include "LList.h"
#include "vehicle.h"
#include <iomanip>
using namespace std;

vehicle.h

#pragma once
#include <string>
#include "windows.h"
//#include "LList.h"
template<class registration = int>


class Vehicle
{
public: 
    typedef enum { Car, Van } vehicleType;

protected:
    vehicleType make;
    char model;
    bool rent;
    double engineSize;
    int registration;



public: 
    Vehicle(vehicleType make) : model(""), registration(reg), engineSize(engine), make(make), rented(false){}
    char getMakeModel();
    bool getRented;
    bool setRented(bool rent);
    int getEngineSize();
    int getRegistration();
    ~Vehicle();

    void listVehicle();
    void removeVehicle(int deleteVehicle);
    void addVehicle();
    void bookVehicle();
    void displayDetails(int registration);
    void listNonRented();
    void listFiveDoor();
    void listRentedFordVan();
};    

    void linkedList::insertNode(node* newNode)
    {
        newNode->nextNode = head;
        head = newNode;
    }

    bool linkedList::deleteNode(int deleteVehicle)
    {
        node* beforeNode = head;
        node* thisNode = head;
        bool found = false;


        while ((thisNode != NULL) && !found)
        {
            if (thisNode->data == deleteVehicle)
                found = true;
            else
            {
                beforeNode = thisNode;
                thisNode = thisNode->nextNode;
            }
        }


        if (found)
        {
            if (thisNode == head)
            {
                node* oldHead = head;
                head = head->nextNode;
                delete oldHead;
            }
            else
            {
                beforeNode->nextNode = thisNode->nextNode;
                delete thisNode;
            }
            return true;    
        }
        return false;       
    }

    void linkedList:: displayList()
    {

        node* thisNode = head;

        if (head == NULL)
        {
            cout << "\nThe list is empty\n";
        }
        else
            cout << "\tMake\tModel\tRegistration Number\tEngine Size\tRented?";


        do
        {
            cout << setw(30) << left << thisNode->make;
            cout << setw(25) << left << thisNode->model;
            cout << setw(20) << left << thisNode->registration;
            cout << setw(15) << left << thisNode->engine;
            //cout << setw(10) << left << thisNode->rented;


        } while (thisNode != NULL);
        {
            cout << "\n\n";
        }
    }