【发布时间】：2011-07-14 15:53:35
【问题描述】：
当我为链表编译代码时，我得到了一堆未定义的引用错误。代码如下。我一直在编译这两个语句：
g++ test.cpp
还有
g++ LinearNode.h LinearNode.cpp LinkedList.h LinkedList.cpp test.cpp
我真的不明白为什么会出现这些错误，因为我对 C++ 中的类真的很生疏。我真的需要一些帮助。
线性节点.h：
#ifndef LINEARNODE_H
#define LINEARNODE_H
#include<iostream>
using namespace std;
class LinearNode
{
public:
//Constructor for the LinearNode class that takes no arguments
LinearNode();
//Constructor for the LinearNode class that takes the element as an argument
LinearNode(int el);
//returns the next node in the set.
LinearNode* getNext();
//returns the previous node in the set
LinearNode* getPrevious();
//sets the next element in the set
void setNext(LinearNode* node);
//sets the previous element in the set
void setPrevious(LinearNode* node);
//sets the element of the node
void setElement(int el);
//gets the element of the node
int getElement();
private:
LinearNode* next;
LinearNode* previous;
int element;
};//ends the LinearNode class
#endif
线性节点.cpp：
#ifndef LINEARNODE_cpp
#define LINEARNODE_cpp
#include<iostream>
#include"LinearNode.h"
using namespace std;
//Constructor for LinearNode, sets next and element to initialized states
LinearNode::LinearNode()
{
next = NULL;
element = 0;
}//ends LinearNode default constructor
//Constructor for LinearNode takes an element as argument.
LinearNode::LinearNode(int el)
{
next = NULL;
previous = NULL;
element = 0;
}//ends LinearNode constructor
//returns the next element in the structure
LinearNode* LinearNode::getNext()
{
return next;
}//ends getNext function
//returns previous element in structure
LinearNode* LinearNode::getPrevious()
{
return previous;
}//ends getPrevious function
//sets the next variable for the node
void LinearNode::setNext(LinearNode* node)
{
next = node;
}//ends the setNext function
//sets previous for the node
void LinearNode::setPrevious(LinearNode* node)
{
previous = node;
}//ends the setPrevious function
//returns element of the node
int LinearNode::getElement()
{
return element;
}//ends the getelement function
//sets the element of the node
void LinearNode::setElement(int el)
{
element = el;
}//ends the setElement function
#endif
LinkedList.h：
#ifndef LINKEDLIST_H
#define LINKEDLIST_H
#include<iostream>
#include"LinearNode.h"
using namespace std;
class LinkedList
{
public:
LinkedList();
void add(int element);
int removie (int element);
private:
int count;
LinearNode *contents;
};//ends the class linked list
#endif
LinkedList.cpp：
#ifndef LINKEDLIST_CPP
#define LINKEDLIST_CPP
#include<iostream>
#include"LinearNode.h"
#include"LinkedList.h"
using namespace std;
//linkedlist constructor for an empty linked list
LinkedList::LinkedList()
{
count = 0;
contents = NULL;
}//ends the constructor
//adds an element to the front of the linked list
void LinkedList::add(int element)
{
int found = 0, current = 0;
while( (found == 0) && (current !=count) )
{
if (contents.getElement() == element)
found = 1;
else
{
contents = contents.getNext();
current++;
}//ends the else statement
}//ends the while loop
if (found == 0)
{
LinearNode node = new LinearNode(element);
node.setNext(contents);
contents.setPrevious(node);
count++;
}//ends the found == 0 if statment
}//ends the add function
//this function removes one element from the linked list.
int LinearNode::remove(int element)
{
int found = 0;
if (count == 0)
cout << "The list is empty" << endl;
else
{
if (contents.getElement() == element)
{
result = contents.getElement();
contents = contents.getNext();
}//ends the contents.getElement() == element
else
{
previous = contents;
current = contents.getNext();
for (int index = 0; ( (index < count) && (found == 0) )index++)
if (current.getElement() = element)
found = 1;
else
{
previous = current;
current = current.getNext();
}//ends the else statement
if (found == 0)
cout << "The element is not in the list" << endl;
else
{
result = current.getElement();
previous.setNext(current.getNext());
}//ends else statement
}//ends the else stamtement
count--;
}//ends the else statement of count == 0
return result;
}//ends the remove function
#endif
test.cpp:
#include<iostream>
#include"LinearNode.h"
#include"LinkedList.h"
using namespace std;
int main()
{
LinearNode node1, node2, node3, move;
LinkedList list;
node1.setElement(1);
node2.setElement(2);
node3.setElement(3);
}
【问题讨论】：
-
首先——不要把“.h”文件作为编译器的参数。它们已经包含在您的“.cpp”文件中。缺少哪些参考资料？您遇到的链接器错误是什么？
-
另外，从不将
using namespace std;放入.h文件中。 -
下次也粘贴错误信息。
-
我在收到
undefined reference to错误时遇到了类似的问题，结果我忘记在.h中包含带有代码的.cpp。 -
@Avamander 那是错误的方式。您将头文件（即
.h）包含在源文件（即.cpp）中，而不是相反。