我第一次尝试正确进行模块化编程时遇到了问题......
我想知道是否有人可以就如何解决问题提出一个可能的方向
这是我的代码，它再次来自 Laszlo 的计算几何书 ..我所做的唯一不同是将它分成更小的部分和一个单元头文件
编码
头文件.h
#ifndef NULL
#define NULL 0
#endif
#ifndef A_H
#define A_H
// -----Definition of Node Class ----------------------------------
class Node{
protected:
Node *_prev;
Node * _next;
static int cindex;
public:
int index;
Node(void);
virtual ~Node(void);
Node *next(void); // accessor
Node *prev(void); //accessor
Node *insert(Node*);
Node*remove(void);
void splice (Node*);
};
// ------ end of definition of Node --------------------
//======================================================
//----------Start of Definition of ListNode class ------
template < class T > class List;
template<class T> class ListNode: public Node {
public:
T _val;
ListNode(T val);
friend class List<T>;
};
// ------ End of Definition of ListNode class --------------------
//====================================================++
//----------Start of Definition of List class ------
template<class T> class List {
private:
ListNode<T> *header;
ListNode<T> *win;
int _length;
public:
List(void);
~List(void);
T insert(T);
T append(T);
T prepend(T);
List * append(List*);
T remove(void);
void val(T);
T val(void);
T next(void);
T prev(void);
T first(void);
T last(void);
int length(void);
bool isFirst(void);
bool isLast(void);
bool isHead(void);
};
#endif
节点.cpp
#include "header.h"
int Node::cindex=0;
Node::Node(void) :
_next(this), _prev(this)
{index=cindex++;}
Node::~Node(void) {}
Node* Node:: next(void)
{
return _next;
}
Node* Node::prev(void)
{
return _prev;
}
Node *Node::insert(Node*b){
b->_next=_next;
_next->_prev=b;
b->_prev=this;
_next=b;
return b;
}
Node*Node::remove(void)
{
_prev->_next=_next;
_next->_prev=_prev;
_next->_prev=this;
return this;
}
LstNode.cpp
#include "header.h"
template <class T> List <T> :: List(void): _length(0) //constructor for list
{
header =new ListNode<T>(NULL); //mind you this uses the LIstNode class
win=header;
}
template<class T> List <T>::~ List(void) // weird destructor
{
while (length()>0) {
first();remove();
}
delete header;
}
template <class T> T List <T> ::insert(T val)
{
win->insert( new ListNode <T> (val));
++_length;
return val;
}
template <class T> T List <T>::prepend(T val)
{
header->insert(new ListNode <T> (val));
++_length;
return val;
}
template <class T> T List <T>::append(T val)
{
header->prev()->insert(new ListNode <T> (val));
++_length;
return val;
}
template<class T> List <T>* List <T>::append(List<T>*l)
{
ListNode<T> *a =(ListNode<T>*)header->prev();
a->splice(l->header);
_length+=_length;
l->header-remove();
l->_length=0;
l->win=header;
return this;
}
template <class T> void List<T>::val(T v)
{
if (win!=header)
win->_val=v;
}
template <class T> T List<T>::val(void)
{
return win->_val;
}
template <class T> T List <T>:: next(void)
{
win=(ListNode <T>*)win->next();
return win->_val;
}
template <class T> T List <T>:: prev(void)
{
win=(ListNode <T>*)win->prev();
return win->_val;
}
template <class T> T List<T>::first(void)
{
win=(ListNode <T>*)header->next();
return win->_val;
}
template <class T> T List<T>::last(void)
{
win=(ListNode <T>*)header->prev();
return win->_val;
}
template <class T> int List <T>::length(void)
{
return _length;
}
template< class T> bool List <T> ::isFirst(void)
{
return (win==header->next()) &&(_length>0);
}
template< class T> bool List <T> ::isLast(void)
{
return (win==header->prev()) &&(_length>0);
}
template <class T> bool List <T>::isHead(void)
{
return (win == header);
}
实验.cpp
#include <iostream>
#include "header.h"
int main()
{
List <int> dunder;
dunder.insert(9);
return 0;
}
问题
我首先使用通用命令（单独）将所有这些文件转换为目标文件，g++ -o file.cpp然后我这样做了g++ output.o output2.o ..
，这是我得到的错误：
experiment.o: In function `main':
experiment.cpp:(.text+0x11): undefined reference to `List<int>::List()'
experiment.cpp:(.text+0x22): undefined reference to `List<int>::insert(int)'
experiment.cpp:(.text+0x33): undefined reference to `List<int>::~List()'
experiment.cpp:(.text+0x46): undefined reference to `List<int>::~List()'
collect2: error: ld returned 1 exit status