C++ :: Double Linked List - Node Undeclared
Apr 2, 2013
I am developing a double linked list in C ( development environment ) is QT with mingw32 4.7 gcc / g++ compiler , in the header file I have defined struct as follows :
Code:
#ifndef LINKEDLIST_H
#define LINKEDLIST_H
#include <stdlib.h>
#include <sys/stat.h>
#include <signal.h>
#ifndef NULL
[Code] ....
When compiling I am getting the following error : 'NODE' undeclared (first use in this function)
and
each undeclared identifier is reported only once for each function it appears in
I have also attached the screen shot from the QT IDE
look's like the compiler is not able to pick up the definition of NODE structure , same happens in Netbeans IDE , interesting thing is if change the source file from c to cpp the error goes away .
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Aug 22, 2014
I am trying this without a head/start pointer which would generally hold the address of first node. I have 3 nodes here from which I am trying to delete last node, but its not happening. I might be wrong in my logic and this is my first linked list program.
#include <stdio.h>
#include <stdlib.h>
struct dll{
struct dll *prev;
int data;
struct dll *next;
[Code] ....
output::::
add of p1::0x9605008 add of p2::0x9605018 add of p3::0x9605028 add of p1->prev::(nil) add of p1->next::0x9605018 add of p2->prev::0x9605008 add of p2->next::0x9605028 add of p3->prev::0x9605018 add of p3->next::(nil)
no of nodes 3
enter the addresss of node to delete it
0x9605028
after deletion attempted
add of p1::0x9605028 add of p2::0x9605018 add of p3::0x9605028 add of p1->prev::0x9605018 add of p1->next::(nil) add of p2->prev::0x9605008 add of p2->next::0x9605028 add of p3->prev::0x9605018 add of p3->next::(nil)
no of nodes 3
In this example i am trying to delete the node 3 which is p3, by deleting its address 0x9605028. But after deletion the node count is still 3 and addresses are like unexpected!
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May 30, 2013
I dynamically allocate a new list in the recMergeSort function which should run a constructor but when it get to the functions that use it, I get error C2065: 'otherHead' : undeclared identifier. I have tried setting it to NULL and it didn't work. I even copied the default constructor to a set function and I still get the errors.
Code:
template<class Type>
void unorderedLinkedList<Type>::recMergeSort(nodeType<Type>* &head) {
otherHead = new nodeType<Type>;
if (head !=NULL)
if (head->link != NULL)
[Code] ....
wonder if I'm sending the correct data type. Here is the heading of the functions that I'm using from the book.
Code:
void unorderedLinkedList<Type>::divideList(nodeType<Type>* first1,
nodeType<Type>* first2)
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Dec 5, 2014
I create A program that will Add and Display the Link List but I have problem on it. If I add it will inserted in the prev node not in the next node. Here's my source code.
#include <stdio.h>
typedef struct Member {
int id;
char name[256];
struct Member *next;
[Code] ....
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Apr 19, 2013
I have a struct with some select student information. My wish is to be able to have the user type in a surname from the list, and for that entry to be deleted. However I am slipping up for some reason.
Here is the start of my program showing my struct:
Code:
#include <stdio.h>
#include <string.h>
#define NAME_LEN 30
#define LINE_LEN 80
struct record {
[Code] ....
I get the following errors in my while loop as well as the if statement below that loop:
-invalid operands to binary !=
-invalid type of argument '->'
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May 17, 2014
This is what I have at the moment which works as I would like but wondering if there is a better way of handling? Currently just making sure I know linked-lists well enough.
Code:
void push_to_end( node_t * headRef, int val ) {
node_t * tail = headRef;
node_t * new_node = malloc( sizeof ( node_t ));
while( headRef != NULL ) {
[Code].....
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Aug 12, 2013
I'm trying to impliment a simple singly linked list, then allow a user to add a new node. I have mocked up a siimple example to illustrate my point using Linked Lists...
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct node {
int x;
struct node *next;
[Code] ....
So I have done things similatr to this in C# and Java but not in C. There maybe some parts of this I'm sure some will disagree with in terms of buffers,overflow etc. but it's just the linked list part that I am interested in at the moment, I am only doing it like this because when it works, I will be extracting the working linked list stuff into another program that can deal with its I/O etc.
I have tried to comment as best I can to demonstarte my intentions and understandings per line of code. The add function needs to add a node of value x that the user has input, and add that to the end of the list - I'm sure that the print function is not doing all its supposed to do...
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Mar 2, 2013
If p is a pointer pointing a node to be deleted, then what's wrong in the following code:
cout << "Do you want to delete this record? (y/n) ";
if (getch() == 'y' || getch() == 'Y'){// Delete record.
if (p == *ph){//If first node is to be deleted.
*ph = (*ph)->next;
delete p;
[Code] .....
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Feb 27, 2015
I have to write a program which has the user be able to enter a specific value at a specific position of the linkedlist, replacing that node with the user defined value
EX: Enter the value 5 at 2nd node, which will override the old value at the 2nd node with the new one
I am getting a compiler error which terminates my program right after the user presses the return key after he/she has given a position to change the value
Error: Unhandled exception at 0x013C50C1 in Linked(1).exe: 0xC0000005: Access violation reading location 0x0000812B.
I am not going to show the whole code as the problem resides solely on the insert function:
void TheNode::insert(double num, int choice) {
int post = 0;
MyNode *ptr = new MyNode;
(*ptr).value = num;
MyNode *previous = head;
MyNode *current = head->next;
[Code] .....
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Jan 27, 2013
I have a function that append node to a linked list like this:
struct ListNode{
int value;
struct ListNode* next;
};
void appendNode(struct ListNode* head, int num){
[code] ....
when I use it, the head in main() does not change its address and it's still pointing to NULL. Why??
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Jul 10, 2014
Still toying with my self-coded linked list class and now another question: should I delete each node of my class with the delete in the class destructor or is it done automatically when the main() function ends?
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Oct 24, 2014
How to remove node from linked list. I am trying to implement this in a file record to remove data from struct..I dont know how addressing in linked list work for structs;
#include <iostream>
#include<fstream>
#include<cstring>
#include<cstdlib>
using namespace std;
struct node{
int val;
[Code] ....
segmentation fault
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Oct 25, 2013
I have a problem with inserting a node between two nodes.
Code:
#include <stdio.h>
#include <stdlib.h>
struct listelem {
int nbr;
struct listelem *next;
[Code] ....
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Mar 6, 2015
I am having trouble adding a second node to a doubly linked list. I define my list as follows:
Code:
typedef struct Node {
char command[256];
int length;
struct Node *prev;
struct Node *next;
} userInput;
}
[code]...
Now, when I iterate back through my list (I want to start at the tail and work my way towards the head), I can only ever get the 1st node to print, then the 2nd node is garbage, which means, to me, that I've linked something wrong.
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Aug 30, 2013
While I know that linked lists seem to be a fairly common problem area among beginner C programmers, most examples that I have come across abstract the sorting of a linked list to a separate function which is sadly not what I am trying to do.
The code below is my attempt to have the nodes inserted into their correct place so that once all nodes have been inserted they are already in a sorted order.
Code:
int main(int argc, char *argv[])
{
struct node_t* dict_head;
struct node_t* traversor;
struct node_t* newnode;
int list_size = 0, insert_key, search_key, delete_key, x;
char insert_word[WORDLEN];
/*Opening the dictionary file provided by the command line argument */
FILE *fp;
fp = fopen(argv[1], "r");
[Code]....
The problem is as follows. When you provide it with input in which the first word scanned is any other word than that which would be placed at the front of the list, it works as intended. For example.
7 world
0 ant
3 kodak
1 best
6 the
2 is
Produces ant -> best->is->kodak->best->world
However, swapping ant and world in the above input gives:
world->best->is->kodak->best->world
In regards to why I have my head node set as a node without a word or a key, it was suggested that I make it so that the first node inserted is set to be the head of the list and then changed as sorting required, yet this caused only additional problems.
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Oct 18, 2014
I was trying to write a function in C to delete a node(only from the middle) from a Singly Linked List. I wrote one but not sure if the code will work fine under all test conditions. I have tested it and shows no error so far.
Code:
void deleteAt(struct node *root, int number){
while(root->link != NULL) {
if(root->link->item == number) //checks if the next node is the element to be deleted {
root->link = root->link->link; //points the link of the element to be deleted to the element before the element to be deleted
}
else
root = root->link;
} }
Or is there a better way to do this?
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Sep 19, 2013
I need to delete the Nth node from a doubly linked list. I know I just cant delete it out right. I have all the goodies including a templetized node class. This is the code we're given:
template <typename T>
void doublyLinkedList<T>::deleteKthElement(const int item) {
}
It accepts an int, and should go to the Nth node and delete it.
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May 1, 2013
I am trying to delete a node from the end of a Linked List but I have some problems. Every node has it's unique code. Here is what I do:
1. Ask the user for the unique code of the node.
2. Ask him if he wants to change the data in it or delete the whole node.
3. If he chooses to delete it, I do this:
//let's say that temp1 points to the node
List *temp2 = temp1;
temp1 = temp1->next;
delete temp2;
And it's just not deleting the node.
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Oct 17, 2014
i am trying to develop a doubly linked list class. I became stuck at a few of the functions as well as the main.cpp file. i have to insert a character sentence "TRICK OR TREAT" spaces included. I am stuck on the display and the listsize functions and im unsure if my insert has the head node in it. The function parameters were given to us and most of this code was given from a single linked list.
//node.h
#pragma once
class Node
{
publi
[Code].....
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Sep 8, 2014
I would like my function to return the data that was deleted. I have this code at the moment, where value_type is just an alias for int at the moment:
node::value_type linkedlist::removeFromHead(){
node* temp_head;
node::value_type data;
data = head_ptr->getData();
[Code] .....
When I try to use this function though, I get a segfault.
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Mar 26, 2014
I am studying this sample code for linked list class node implementation. I am not 100% sure how this code keeps track of the head node. Here's what I know so far, and if you want to add/correct anything feel free to do so:
class Node {
public:
Node(); // constructor of class node without arguments
Node(int, Node*); //constructor with arguments of int type and a pointer node type
Node* next() const;
void setNext(Node*); //member fun, returning a pointer of node type
void setKey(int);
[Code] ......
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Nov 30, 2014
Why is it sufficient to only have a pointer to the last node of a doubly linked list?
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Sep 6, 2014
I'm trying to calculate the total price of books contained in a linked list. I've tried getTotal() function in linked list but error: no match for 'operator+=' in 'total += ptr->Node<Book>::info'| occurred. How can I access the price in the node and then calculate the total price.
Here is part of my code :
Book class
class Book {
protected :
int id;
string title;
double price;
string bookStatus;
[code]....
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Nov 30, 2014
Why is it sufficient to only have a pointer to the last node of the list?
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Mar 30, 2015
I'm having a bit of an issue here. I have a linked list where each node contains a pointer to a string (which has been malloc'd when the node was created and inserted) and a pointer to the next node in the linked list.
I'm creating a function which will free the node (or effectively delete it). However, I'm receiving a free(): invalid pointer error.
My function:
void removeNode(node *(*nodeToRemove))
{
free((*nodeToRemove)->data);
(*nodeToRemove)->next = NULL;
free(*nodeToRemove);
}
Is this how I should go about freeing this node?
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Jan 2, 2014
I'm having a small issue here with my linked list.I built a linked list with strings and it worked perfectly.Now since i'm using strtok() to separate the string.for now here's what i've got:
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct dict_word *word;
typedef struct node *Node;
typedef struct double_linked_list *DLL;
}
[code]....
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