堆栈链接错误问题

Question

当我运行程序时，编译器会给出这些错误 -

  "Stack<int>::push(int&)", referenced from:
      _main in main.o
  "Stack<int>::~Stack()", referenced from:
      _main in main.o
      _main in main.o
  "Stack<int>::Stack()", referenced from:
      _main in main.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

编译时我没有收到任何错误。

代码如下 -

/*
 *  Stack.h
 *  Stack
 *
 *  Created by Sterling McLeod on 2/1/11.
 *  Copyright 2011 University of North Carolina at Charlotte. All rights reserved.
 *
 */
#ifndef STACK_H
#define STACK_H

#include <exception>

template<typename T>
class Stack {

public:


    class EmptyTreeException : public std::exception {
    public:
        virtual const char* what() const throw();
    };  //end exception



    Stack();
    ~Stack();

    T peek();
    bool isEmpty();
    int size();

    void push(T&);
    T pop();

private:
    T* top; 
    int count;
};
#endif STACK_H
[/code]
[code]
/*
 *  Stack.cpp
 *  Stack
 *
 *  Created by Sterling McLeod on 2/1/11.
 *  Copyright 2011 University of North Carolina at Charlotte. All rights reserved.
 *
 */

#include "Stack.h"

template <typename T>
const char* Stack<T>::EmptyTreeException::what() const throw() {
    return "The stack is empty!\n";
}


template <typename T>
Stack<T>::Stack() : count(0) {}
template <typename T>
Stack<T>::~Stack() {delete [] top;}


template <typename T>
T Stack<T>::peek() {return top[count];}

template <typename T>
bool Stack<T>::isEmpty() {return count == 0;}

template <typename T>
int Stack<T>::size() {return count;}




template <typename T>
void Stack<T>::push(T& n) {
    top[++count] = n;
}   //END PUSH


template <typename T>
T Stack<T>::pop() {
    if(isEmpty())
        throw EmptyTreeException();
    T result = top[count];
    top[count--] = NULL;
    return result;
}   //END POP
[/code]
[code]
#include <iostream>
#include "Stack.h"

int main (int argc, char * const argv[]) {
    Stack<int> s;
    int a = 10;
    while(a < 50) {
        s.push(a);
        a += 10;
    }   //end
    return 0;
}

我不知道为什么这不起作用......看起来它对我来说应该没有问题。如果有人能给我一个提示那就太好了。谢谢。

Answer 1

简而言之：模板定义应该放在头文件中，否则编译器不会实例化它们，链接器会哭。

有关更多详细信息，请参阅 http://www.parashift.com/ c++-faq-lite/templates.html#faq-35.12。