Tanımsız Referans

Question

Bağlantılı bir liste için kodumu derlediğimde, bir dizi tanımlanmamış başvuru hatası alıyorum. Kod aşağıda. Ben Bu açıklamaların her ikisiyle derleme edilmiştir:

g++ test.cpp 

yanı sıra

g++ LinearNode.h LinearNode.cpp LinkedList.h LinkedList.cpp test.cpp 

Bu hataları alıyorum neden C sınıfları gerçekten paslı çünkü ben gerçekten ++ anlamıyorum. Gerçekten biraz yardım edebilirim.

LinearNode.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 

LinearNode.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); 
} 

Answer 1

1. Genellikle korumaları olmayan kaynak dosyaları (yani, .cpp) için (diğer bir deyişle, .h) başlık dosyaları içindir başlıklarını.
2. Kaynak dosyalarda gerekli standart üstbilgileri ve ad alanlarını ekleyin.

LinearNode.h:

#ifndef LINEARNODE_H 
#define LINEARNODE_H 

class LinearNode 
{ 
    // ..... 
}; 

#endif 

LinearNode.cpp:

#include "LinearNode.h" 
#include <iostream> 
using namespace std; 
// And now the definitions 

LinkedList.h:

#ifndef LINKEDLIST_H 
#define LINKEDLIST_H 

class LinearNode; // Forward Declaration 
class LinkedList 
{ 
    // ... 
}; 

#endif 

LinkedList.cpp

#include "LinearNode.h" 
#include "LinkedList.h" 
#include <iostream> 
using namespace std; 

// Definitions 

test.cpp kaynak dosyası ince olmasıdır. Başlık dosyalarının hiçbir zaman derlenmediğini unutmayın. Varsayarsak tüm dosyalar tek klasörde -

g++ LinearNode.cpp LinkedList.cpp test.cpp -o exe.out 

Answer 2

g++ test.cpp LinearNode.cpp LinkedList.cpp -o test 

Answer 3

bu hatayı almaya bir diğer yolu ise yanlışlıkla anonim bir ad alanında bir şeyin tanımını yazarak:

foo.h:

namespace foo { 
    void bar(); 
} 

foo.cc:

namespace foo { 
    namespace { // wrong 
     void bar() { cout << "hello"; }; 
    } 
} 

diğer.cc dosyası:

#include "foo.h" 

void baz() { 
    foo::bar(); 
}