[英]Undefined Reference to
當我為鏈表編譯代碼時,我收到一堆未定義的引用錯誤。 代碼如下。 我一直在編譯這兩個語句:
g++ test.cpp
也
g++ LinearNode.h LinearNode.cpp LinkedList.h LinkedList.cpp test.cpp
我真的不明白為什么我會收到這些錯誤,因為我對 C++ 中的類真的很生疏。 我真的可以使用一些幫助。
線性節點.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
線性節點.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
鏈表.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
鏈表.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
測試.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);
}
.h
)而不是源文件(即.cpp
)。線性節點.h:
#ifndef LINEARNODE_H
#define LINEARNODE_H
class LinearNode
{
// .....
};
#endif
線性節點.cpp:
#include "LinearNode.h"
#include <iostream>
using namespace std;
// And now the definitions
鏈表.h:
#ifndef LINKEDLIST_H
#define LINKEDLIST_H
class LinearNode; // Forward Declaration
class LinkedList
{
// ...
};
#endif
鏈表文件
#include "LinearNode.h"
#include "LinkedList.h"
#include <iostream>
using namespace std;
// Definitions
test.cpp是源文件很好。 請注意,頭文件永遠不會被編譯。 假設所有文件都在一個文件夾中 -
g++ LinearNode.cpp LinkedList.cpp test.cpp -o exe.out
g++ test.cpp LinearNode.cpp LinkedList.cpp -o test
我收到此錯誤是因為我的 cpp 文件未添加到 CMakeLists.txt 文件中
獲得此錯誤的另一種方法是意外地在匿名命名空間中編寫某些內容的定義:
foo.h:
namespace foo {
void bar();
}
foo.cc:
namespace foo {
namespace { // wrong
void bar() { cout << "hello"; };
}
}
其他.cc文件:
#include "foo.h"
void baz() {
foo::bar();
}
您的LinkedList.h一個錯字,你寫removie,而不是刪除在你的CPP文件。 應該
int remove (int element);
代替
int removie (int element);
當我忘記將我創建的新 .h/.c 文件添加到介子配方時遇到了這個問題,所以這只是一個友好的提醒。
嘗試刪除構造函數和析構函數,它對我有用....
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