C++ - LNK2019 错误未解析的外部符号 [模板类的构造函数和析构函数] 在函数 _main 中引用

Hey all -- I'm using Visual Studio 2010 and having trouble linking a quick-and-dirty Queue implementation. I started with an empty Win32 Console Application, and all files are present in the project. For verbosity, here's the complete code to duplicate my error. I realize some of the code may, in fact, be wrong. I haven't had a chance to test it yet because I haven't yet been able to link it.

队列.hpp

#ifndef ERROR_CODE
#define ERROR_CODE
enum Error_Code
{
    Success,
    Underflow,
    Overflow
};
#endif // ERROR_CODE

#ifndef QUEUE
#define QUEUE
template<class T>
struct Queue_Node
{
    T data;
    Queue_Node *next;

    Queue_Node()
    {
        next = NULL;
    }
    Queue_Node(T pData)
    {
        data = pData;
        next = NULL;
    }
    Queue_Node(T pData, Queue_Node *pNext)
    {
        data = pData;
        next = pNext;
    }
};

template<class T>
class Queue
{
public:
    Queue();
    Error_Code Serve();
    Error_Code Append(T item);
    T Front();
    ~Queue();

private:
    void Rescursive_Destroy(Queue_Node<T> *entry);
    Queue_Node<T> *front, *rear;
};
#endif // QUEUE

队列.cpp

#include "Queue.hpp"

template <class T>
Queue<T>::Queue()
{
    this->front = this->rear = NULL;
}

template<class T>
Error_Code Queue<T>::Serve()
{
    if(front == NULL)
        return Underflow;

    Queue_Node *temp = this->front;
    this->front = this->front->next;
    delete temp;
}

template<class T>
Error_Code Queue<T>::Append(T item)
{
    Queue_Node *temp = new Queue_Node(item);
    if(!temp)
        return Overflow;

    if(this->rear != NULL)
        this->rear->next = temp;
    this->rear = temp;

    return Success;
}

template<class T>
T Queue<T>::Front()
{
    if(this->front == NULL)
        return Underflow;
    return this->front->data;
}

template<class T>
Queue<T>::~Queue()
{
    this->Rescursive_Destroy(this->front);
}

template<class T>
void Queue<T>::Rescursive_Destroy(Queue_Node<T> *entry)
{
    if(entry != NULL)
    {
        this->Recursive_Destroy(entry->next);
        delete entry;
    }
}

程序.cpp

#include "Queue.hpp"

int main()
{
    Queue<int> steve;
    return 0;
}

还有错误...

Error   1   error LNK2019: unresolved external symbol "public: __thiscall Queue<int>::~Queue<int>(void)" (??1?$Queue@H@@QAE@XZ) referenced in function _main    C:[omitted]Project2_2Project2_2program.obj  Project2_2
Error   2   error LNK2019: unresolved external symbol "public: __thiscall Queue<int>::Queue<int>(void)" (??0?$Queue@H@@QAE@XZ) referenced in function _main C:[omitted]Project2_2Project2_2program.obj  Project2_2

推荐答案

你为什么不关注 "包含模型"?我建议您遵循该模型.编译器需要访问整个模板定义(不仅仅是签名)，以便为模板的每个实例化生成代码，因此您需要将函数的定义移动到您的头文件中.