正确的方法来模板化头和cpp？

Question

我已经在头文件中找到了一个模板化的优先级队列;

template <typename ElemType>
class HeapPQueue {
public:
    HeapPQueue<ElemType>();
    ~HeapPQueue<ElemType>();

等

这是在cpp文件中;

#include "pqueue-heap.h"
#include "cmpfn.h"
#include "error.h"
using namespace std;

template <typename ElemType>
HeapPQueue<ElemType>::HeapPQueue() {
    capacity = START_CAPACITY;
    heap = new ElemType[capacity];
    logSize = 0;
}

template <typename ElemType>
HeapPQueue<ElemType>::~HeapPQueue() {
    delete[] heap;

}

我收到错误消息“未知类型名称HeapPQueue”。为什么呢？