I am just starting my implementation of my Skip List, and I have tried everything to get rid of this error. My Build Succeeds, but when I put "SList p" into my main program, it fails and said linked reference ld error. What is the problem?
Here is my .h file
#ifndef SLIST_H
#define SLIST_H
#include <string>
#include <fstream>
class SList {
public:
SList();
// overloaded assignment operator
SList& operator = (const SList&);
// copy constructor
SList(const SList&);
// destructor
~SList();
private:
const static int DUMMY_VALUE = -1000;
struct Node {
int data;
Node *next;
};
struct upperNode {
upperNode *next;
Node *down;
};
Node *head;
upperNode *upperHead;
int length;
};
#endif // SLIST_H
__
My .cpp file
#include "SList.h"
SList::SList() {
length = 0;
head->data = DUMMY_VALUE;
head->next = nullptr;
upperHead->down = head;
upperHead->next = nullptr;
}
and my main
#include "SList.h"
#include <iostream>
int main() {
SList p;
return 0;
}
What am I missing here? I feel like it is terribly obvious I just need a second set of eyes. Thank you.
You have declared a copy assignment operator, a copy constructor and a destructor, but you don't provide implementations.
Related
Okay so I am trying to understand the internals of a LinkedList and I have made two classes, Node and LinkedList. For some reason, the node constructor is spitting out an int rather than a node.
Node* head; // throws " error: invalid conversion from 'int' to 'Node*' [-fpermissive]"
int whyDoesThisWork = new Node(); //by god this works
The first case was annoying, but the second is actually kind of funny.
Here is my Node.h:
#ifndef NODE_H_
#define NODE_H_
class Node {
public:
Node();
Node(int val);
~Node();
int value;
Node* next;
};
#endif /* NODE_H_ */
My Node.cpp:
#include "Node.h"
#include <stdlib.h>
Node::Node() {
this->value = 0;
this->next = NULL;
}
Node::Node(int val) {
this->value = val;
this->next = NULL;
}
I am absolutely clueless to why a Node constructor is returning an int. Any insight would be appreciated
Edit
Here is my driver file:
#include <iostream>
#include "LinkedList.h"
#include "Node.h"
using namespace std;
int main() {
Node* head;
int* val = new Node();
return 0;
}
Node* head; is just a declaration of an uninitialized pointer, it can't throw a conversion error.
int whyDoesThisWork = new Node(); will fail to compile, because a pointer cannot be assigned to an int (without an explicit type-cast). This is a type mismatch. Are you sure the compiler is not actually saying error: invalid conversion from 'Node*' to 'int' instead?
int* val = new Node(); will also fail to compile, because a Node* pointer is not an int* pointer. This is also a type mismatch.
C++ is a strongly typed language. It is not forgiving of type mismatches, unless implicit conversions are defined for the types in question, which is not the case here.
I'm new in C++ and I have something to do with a linked list, and I don't know why it doesn't work, need help from a prof :O)
Here's my .h
#ifndef UnCube_H
#define UnCube_H
using namespace std;
class ACube{
public:
ACube();
struct Thecube;
private:
void PrintList();
};
#endif
My ACube.cpp
#include <iostream>
#include "ACube.h"
ACube::ACube(){
};
struct Thecube{
int base;
int cube;
Thecube * next ;
};
void ACube::PrintList(){
};
and finally my main.cpp
#include <cstdlib>
#include <iostream>
#include "ACube.h"
using namespace std;
int main()
{
ACube * temp;
temp = (ACube*)malloc(sizeof(ACube));
for (int inc=1; inc <=20 ; inc++){
temp->ACube->nombrebase = inc;
temp->cube = inc*inc*inc;
}
system("PAUSE");
return EXIT_SUCCESS;
}
Everything was working fine, but when I add these lines :
temp->ACube->nombrebase = inc;
temp->cube = inc*inc*inc;
I add error saying :
'class ACube' has no member named 'TheCube'
'class ACube' has no member named 'cube'
Can someone help me because I want to create my list and fill the cube with number.
Other thing I want to use THIS. in the print,
Maybe someone can teach me what's wrong and how to do it !
Thanks for any help
You don't need to have a struct inside your class.
#ifndef UnCube_H
#define UnCube_H
using namespace std;
class ACube{
public:
ACube();
int base;
int cube;
ACube * next ;
private:
void PrintList();
};
#endif
ACube.cpp
#include <iostream>
#include "ACube.h"
ACube::ACube(){
};
void ACube::PrintList(){
};
Also, this string is wrong:
temp->ACube->nombrebase = inc;
it should be just:
temp->base = inc;
Last but not least, this code doesn't create a linked list, because you don't do anything with the ACube::next pointer.
There are so many horrible problems in your code, I suggest you should learn more C++ knowledge before writing linked list.
1. What is nombrebase?
I think nobody can answer.
2. You must allocate C++ class by new key word instead of malloc.
new invokes not only allocation but also class constructor, while malloc allocates only.
3. Thecube should been defined inside ACube
Since the code in your main() refers the member cube in class Thecube, main() must know what it is.
4. The member next in class ACube is a pointer which points to what?
What does a pointer point to without initilization? You should initial it in constructor, and destroy it in destructor.
5. temp->ACube
ACube is a class type, you can access member object, but not a type.
6. Never using namespace into a header file
It would make the client of header file has name collision.
The following is the corrected code. Just no compile error and runtime error, but this is NOT linked list:
ACube.h
#ifndef UnCube_H
#define UnCube_H
class ACube{
public:
struct Thecube
{
int base;
int cube;
Thecube * next;
};
ACube();
~ACube();
Thecube *next;
private:
void PrintList();
};
#endif
ACube.cpp
ACube::ACube()
: next(new Thecube)
{
}
ACube::~ACube()
{
delete next;
}
void ACube::PrintList(){
}
main.cpp
#include <cstdlib>
#include <iostream>
#include "ACube.h"
using namespace std;
int main()
{
ACube * temp;
temp = new ACube;
for (int inc = 1; inc <= 20; inc++)
{
temp->next->base = inc; // <-- This is not linked list, you shall modify.
temp->next->cube = inc*inc*inc; // <-- This is not linked list, you shall modify.
}
system("PAUSE");
return EXIT_SUCCESS;
}
my code have error (error C2512: 'Node' : no appropriate default constructor available)
but i have default constructor why ???
my error location commented in code Please help me
Node.h
#pragma once
#include "stat.h"
#include "Automata.h"
#include <cstdlib>
class Node
{
friend class Automata;
friend class stat_a;
friend stat_a* makeauto(char *str);
friend int main();
private:
stat_a* mess;
char data;//harfi ke ba in masir estefadeh mishe :)
Node *next;//node badi dar araye node ha class stat_a :)
public:
Node()
{
mess = NULL;
next = NULL;
};
};
stat.h
#pragma once
#include "Node.h"
#include <iostream>
using namespace std;
class stat_a
{
friend class Automata;
friend class Node;
friend int main();
private:
bool is_final_stat_a; //aya final stat_a hast ???
int stat_a_num; //shomareh halat 0,1,2,...
Node *last; //akharin node dar araye node haye neshan dahande masir
Node *first; //Avalin node dar araye node haye neshan dahande masir
public:
void add(char d,stat_a * a)//ezafeh kardan masiri ke ba estefadeh
{ //az harf (char d ) be halat (stat_a a) miravad
if(first == NULL)
{
first = new Node;//error is here
first->data = d;
first->mess = a;
last=first;
}
else
{
last->next = new Node ;//erorr is here
last=last->next;
last->data=d;
last->next=NULL;
last->mess=a;
}
};
/***********************************************************************/
void print()
{
cout<<stat_a_num<<"========> is final_stat_a : "<<is_final_stat_a<<endl;
Node *a;
a=first;
while(a != NULL)
{
cout<<"========> By '"<<a->data<<"' go to stat "<<a->mess->stat_a_num<<endl;
a=a->next;
}
};
stat_a()
{
last=NULL;
first=NULL;
is_final_stat_a=false;
};
~stat_a(void);
};
I have default constructor available why error
It's a classical example of circular dependency. The header file Node.h depends on the header file stat.h which depends on Node.h and so on.
Since you only declare a pointer variable of type stat_h in Node, you don't need to include the header file for that, it's enough to declare the class stat_a:
#pragma once
#include "Automata.h"
#include <cstdlib>
class stat_a; // Declare the class, so the compiler know there's a class by this name
class Node
{
// ...
private:
stat_a* mess; // Works because you're only declaring a pointer
// ...
public:
// ...
};
Then in the stat.h header when you include Node.h there is no longer a circular dependency.
Replace
Node();
{
mess = NULL;
next = NULL;
}
with
Node()
{
mess = NULL;
next = NULL;
};
It's giving me this error for lines 21 and 22, which are the ones I've noted. Judging from other cases with similar error messages, I've got a syntax error somewhere. I just can't figure out what.. Here's my .cpp file:
#include <iostream>
#include <cstdlib>
#include "deque.h"
using namespace std;
struct node{
int data;
node *prev;
node *next;
};
Deque::Deque(){
count = 0;
node->head->next = node->head; //error on this line
node->head->prev = node->head; //and this one
}
Here's my header file:
# ifndef DEQUE_H
# define DEQUE_H
class Deque
{
private:
int count;
class node *head;
public:
Deque();
~Deque();
int size();
void addFirst(int);
void addLast(int);
int removeFirst();
int removeLast();
int getFirst();
int getLast();
};
#endif
Correct code for these lines:
head->next = head;
head->prev = head;
Your variable is named head, and node is its type, but there is no member named node in your class Deque
struct node has no member named head, which is a problem.
Where is your node variable coming from in Dequeue()? Looks undefined given the code that you have posted. node is a type, not a variable.
In C++ there is no need to prefix each declaration of a struct type variable with struct. If it needs to be C compatible you can always typedef the struct as well.
I am trying to build a Linked list application using C++ programming language & features such as inheritance etc.
I have split the interface & implementation in different files but not able to compile.
Below are the list of files
Interface files :- node.h , abstractList.h , singleLinkedList.h
Implementation files: singleLinkedList.cpp
node.h
#ifndef NODE_H
#define NODE_H
#include <iostream>
struct nodeType {
int data;
struct nodeType *next;
}listNode;
#endif
abstractList.h
#ifndef ABSTRACT_LIST_H
#define ABSTRACT_LIST_H
#include <iostream>
#include "node.h"
#include "singleLinkedList.h"
class abstractList {
public:
virtual ~abstractList();
virtual bool isEmpty(Node* ) = 0;
virtual int get(const int&) = 0;
virtual int indexOf(const int& ) = 0;
virtual Node insert(const int& , const int& ) = 0;
virtual void delete(const int& ) = 0;
};
#endif
singleLinkedList.h
#ifndef SINGLE_LIST_H
#define SINGLE_LIST_H
#include <iostream>
#include "node.h"
#include "abstractList.h"
class singleLinkedList : public abstractList {
public:
singleLinkedList();
~singleLinkedList();
Node populateList( );
private:
void checkIndex();
int data;
Node head;
};
#endif
So far i have just coded the populateList() function in the implentation file, here goes the implementation file.
singleLinkedList.cpp
#include <iostream>
#include "node.h"
#include "singleLinkedList.h"
#include "abstractList.h"
Node singleLinkedList :: populateList()
{
Node temp;
int data;
temp = head;
char ch;
std::cout<<"Enter Data? (y/n) " << std::endl;
std::cin>>ch;
while(ch == 'Y' || ch == 'y')
{
std::cout<<"Enter the data that you would like to store.\n"<<std::endl;
std::cin>>data;
temp = new Node();
temp->data = data;
temp->next = head;
head = temp;
std::cout<<"Enter more data?"<<std::endl;
std::cin>>"\n">>ch;
}
return temp;
}
When i give g++ -c singleLinkedList.cpp , i am getting lot of errors. I am pretty sure i have done something stupid. Can anyone please pin point my error?
EDIT: Error Log With specfic issues.
struct nodeType {
int data;
struct nodeType *next;
}listNode;
virtual listNode *insert();
Is the above statement correct?
Thanks
Kelly
delete is a keyword in C++, you can't use it as a method name. You need to use a different name here:
class abstractList {
public:
//...
virtual void delete(const int& ) = 0;
//-----------^^^^^^ rename this.
};
The problem is in your typedef:
typedef listNode *Node;
means that all instances of Node will essentially replaced by listnode*
temp = new Node();
actually reads
temp = new listnode*();
But new Foo() would return a Foo* (because new returns a pointer to memory allocated for an object), meaning that new listnode*() would return a listnode**. temp being a listnode* has no Idea what a listnode** is and complains.
what you want to do is:
Node temp = new listnode();
or forget the typedef altogether:
listnode* temp = new listnode();