C++ 未定义的引用错误，使用模板和类

我正在为明天的考试练习一些编码，因为某种原因我无法运行我的程序。我一直收到一个错误：

未定义的引用..pract\ArrayListType\main.cpp:47:错误：未定义对“ArrayListType:：Print const”的引用

这是我的代码，我到目前为止，从我所看到的，它看起来很好。 尝试注释掉代码行，但无效。 不知道会出什么问题

//头文件：

#ifndef ARRAYLISTTYPE_H
#define ARRAYLISTTYPE_H

using namespace std;


template <class elemType>
class arrayListType
{
public:
    const arrayListType<elemType>& operator= (const arrayListType<elemType>&);
    //Overloads the assignment operator

    bool isEmpty() const;
    //Determines if list is empty

    bool isFull() const;
    //Determines if the list is full

   int listSize() const;
   //Function to determine number of elements in the list

   int maxListsize() const;
   //Function to determine the size of the list

   void Print() const;
   //Function to output the elements in the list

   bool isItemAtEqual(int location, const elemType& item) const;
   //Function to determine if an item entered is the same as another item at a specific location

   void insertAt(int location, elemType& insertItem);
   //Function to insert an item at a specified location

   void insertEnd(const elemType& insertItem);
   //Function to insert an item at the end of the list

   void removeAt(int location);
   //Function to remove an item at a specified location

   void retrieveAt(int location, const elemType& retItem) const;
   //Function to retrieve the item located at the position specified

   void replaceAt(int location, const elemType& repItem);
   //Function to replace a value in the list at a specified location

   void clearList();
   //Function to remove all the elements from the list

   int seqSearch(const elemType& item) const;
   //Function to search the list for a given item

   void insert(const elemType& insertItem);
   //function to insert an item into the list

   void remove(const elemType& removeItem);
   //function to remove an item from the list

   arrayListType(int size = 100);
   //Constructor to initialize the size of the list to 100

   arrayListType(const arrayListType<elemType>& otherList);
   //Copy constructor

  ~arrayListType();
   //Destructor

protected:
   elemType *list;
   int length;
   int maxSize;
};

#endif // ARRAYLISTTYPE_H

//定义文件

#include <iostream>
#include <string>
#include "arraylisttype.h"

using namespace std;

template <class elemType>
bool arrayListType<elemType>::isEmpty() const {
    return (length == 0);
}

template <class elemType>
bool arrayListType<elemType>::isFull() const {
    return (length == maxSize);
}

template <class elemType>
int arrayListType<elemType>::listSize() const {
    return length;
}  

template <class elemType>
int arrayListType<elemType>::maxListsize() const {
    return maxSize;
}
//All the above functions have a running time of O(1) - constant as they will
//produce the same result int eh same time due to only having one line to run.
//_____________________________________________________________________________

template <class elemType> // O(n)
void arrayListType<elemType>::Print() const {
    for (int i = 0; i <length; i++) {
        cout << list[i] << " ";
    }
    cout << endl;
}
//The print function will have a running time of O(n) as it is linear to the size of the list
//and how full the list is.

template <class elemType> // O(1) - constant
bool arrayListType<elemType>::isItemAtEqual(int location, const elemType &item) const {
    return(list[location] == item);
}

template <class elemType> //O(n)
void arrayListType<elemType>::insertAt(int location, elemType &insertItem) {
    if (location < 0 || location >= maxSize)
        cerr << "The position to be inserted at is out of range!";
    else
        if (length >= maxSize)
            cerr << "Cannot insert in a full list";
    else {
        for (int i = length; i > location; i--)
            list[i] = list[i - 1]; // Move elements down.
            list[location] = insertItem; // insert the item at the specified location
            length++;

        }
}

template <class elemType>
void arrayListType<elemType>::insertEnd(const elemType &insertItem) {
    if (length >= maxSize)
        cerr << "Cannot insert in a full list";
    else {
        list[length] = insertItem;
        length++;
    }
}

template <class elemType>
void arrayListType<elemType>::removeAt(int location) {
    if (location < 0 || location >= maxSize)
        cerr << "the location fo the item to be retrieved is out of bounds";
    else {
        for (int i = location; i < length - 1; i++)
            list[i] = list[i+1];
        length--;
    }
}

template <class elemType>
void arrayListType<elemType>::retrieveAt(int location, const elemType& retItem) const {
    if (location < 0 || location >= maxSize)
        cerr << "the location fo the item to be retrieved is out of bounds";
    else (retItem = list[location]);
}

template <class elemType>
void arrayListType<elemType>::replaceAt(int location, const elemType &repItem) {
    if (location < 0 || location >= length)
        cerr << "The location of the item to be replaced is out of bounds.";
    else
        list[location] = repItem;
}

template <class elemType>
void arrayListType<elemType>::clearList() {
    length = 0;
}

template <class elemType>
arrayListType<elemType>::arrayListType(int size) {
    if (size < 0) {
        cerr << "The array size must be positive. creating an array of size 100";
    maxSize = 100;
    }
    else
        maxSize = size;
    length = 0;

    list = new elemType[maxSize];
    assert(list!=NULL);
}

template <class elemType>
arrayListType<elemType>::~arrayListType() {
    delete [] list;
}

template <class elemType>
arrayListType<elemType>::arrayListType(const arrayListType<elemType> &otherList) {
    maxSize = otherList.maxSize;
    length = otherList.length;
    list = new elemType[maxSize];

    for (int j = 0; j < length; j++)
        list[j] = otherList.list[j];
}

template <class elemType>
const arrayListType<elemType>& arrayListType<elemType>::operator=(const arrayListType<elemType>& otherList) {
    if (this != &otherList) {
        delete [] list;
        maxSize = otherList.maxSize;
        length = otherList.length;

        list = new elemType[maxSize];
        assert(list != NULL);

        for (int i = 0; i < length; i++)
            list[i] = otherList.list[i];
    }
    return *this;
}

template <class elemType>
int arrayListType<elemType>::seqSearch(const elemType &item) const {
    int loc;
    bool found = false;

    for (loc = 0; loc < length; loc++)
        if (list[loc] == item) {
            found = true;
            break;
        }
    if (found)
        return loc;
    else
        return -1;
}

template <class elemType>
void arrayListType<elemType>::insert(const elemType &insertItem) {
    int loc;

    if (length == 0)
        list[length++] == insertItem;
    else if (length == maxSize)
        cerr << "Cannot insert into full list.";
    else {
        loc == seqSearch(insertItem);

        if (loc == -1)
            list[length++] = insertItem;
        else
            cerr << "The item to be inserted is already in the list."
                 << "\nNo duplicates are allowed.";
    }
}

template <class elemType>
void arrayListType<elemType>::remove(const elemType &removeItem) {
    int loc;

    if (length == 0)
        cerr << "Cannot delete from an empty list";
    else {
        loc = seqSearch(removeItem);

        if (loc != -1)
            removeItem(loc);
        else
            cout << "The item to be deleted is not int eh list.";
    }
}

//主要

#include <iostream>
#include <string>
#include "arraylisttype.h"

using namespace std;

int main()
{

    arrayListType<int> intList(100);
    arrayListType<string> stringList;

    int number;

    cout << "List 10: Enter 5 integers: ";

    for (int counter = 0; counter < 5; counter++) {
        cin >> number;
        intList.insertAt(counter, number);
    }

    cout << endl;
    cout << "List 19: The list you entered is: ";
    intList.Print();
    cout << endl;

    cout << "Line 20: Enter the item to be deleted: ";
    cin >> number;
    intList.remove(number);
    cout << "Line 23: After removing " << number << ", the lsit is: " << endl;
    intList.Print();
    cout << endl;

    string str;

    cout << "Line 27: Enter 5 strings: ";

    for (int counter = 0; counter < 6; counter++) {
        cin >> str;
        stringList.insertAt(counter, str);
    }

    cout << endl;
    cout << "Line 34: The list you entered is: ";
    stringList.Print();
    cout << endl;

    cout << "Line 37: Enter the string to be deleted: ";
    cin >> str;
    stringList.remove(str);
    cout << "Line 40: After removing " << str << " the list is: " << endl;
    stringList.Print();

    return 0;
}

---

当您使用模板类或方法时，编译器会生成代码，并且编译器需要访问定义。因此，您必须将模板方法定义放入头文件本身，并包括使用它们的位置。模板是编译时特性，而不是运行时特性。模板定义不能与cpp文件隔离。

除上述内容外，为什么定义文件中列出了两次包含项？在出现错误之前，您最近做了什么更改？那你为什么不能准备一份工作呢？