C :: How To Reverse Unidirectional Linked List
Sep 12, 2014
I was assigned to reverse a unidirectional linked list in C, where I'm not allowed to make a copy of the given linked list, or to change the actual data.
The only thing I'm allowed to do is to manipulate the list's pointers. After doing some thinking and scribbling on a piece of paper, I came up with this:
Initialize three pointers: p1,p2,p3, for the first, second and third elements, respectively.
p1->next=NULLwhile (p3 != NULL) do p2->next=p1p1=p2p2=p3p3=p3->nextp2->next=p1return p2
as the head of the reversed list
This is a pseudo code, of course, as I'm less interested in the actual implementation, and more about the algorithm itself. I was wondering if there's a more elegant way of doing this, since this gets quite complicated considering the cases where the list has less than three elements in it.
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Apr 9, 2014
I am trying to create a linked list and then reverse it. So far I have created the link list however I am having difficulties figuring out the steps to reverse it. What is the logic behind reversing this linked list. I am not able to use recursion. I am supposed to create a copy of the linked list with the nodes reversed.
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct charNode {
char data;
struct charNode *nxtNode;
};
[Code]...
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Sep 13, 2013
my code is
#include<stdio.h>
struct node {
int info;
struct node *next, *prev;
};
typedef struct node *nodeptr;
[Code] ....
I have reversed a linked list it is reversing but additional two elements 0,0 are coming, whats going wrong....
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May 3, 2014
I was trying to reverse a linklist in reverse direction using the recursion. I was able to reverse n - 1 element but it is not printing the first one. Below is my code.
Code:
typedef struct linklist {
int data;
linklist *next;
};
void add(int data,linklist **node) {
[code]....
This is happening since recursion is starting from second node, which is due to reason not printing the first one when recursion print values from stack once
node != NULL
Condition is met.
Currently I am using below statement for printing the first element;
reverse_recur(node);
printf("
Print In Reverse Order
%d
",node->data);
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Apr 28, 2015
I have to write a c program that will allow the user to enter names with ages. The name will be no longer than 40 characters. The name and age should be stored in a node of a doubly linked list. I cant use global data. I need to use 3 subroutines. the first one needs to enter the data and pass the head and tail pointers to the subroutine. the next subroutine needs to print the names and ages to the screen and file output.txt from first to last. the last subroutine needs to print out names and ages to the screen and file output.txt from the last to first.
Im getting several errors when i try to run this program. The first subroutine to get the data from the user and build the double linked list. but i seem to be having issues.
#include <stdio.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
int entry(char [][41], int []); // subroutine used for data entry //
void printit(char [][41], int [], int); // subroutine used for data printing //
void reverseprintit(char [][41], int [], int); // subroutine used for reverse data printing //
[Code] .....
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Nov 29, 2014
Implement a recursive function named void printBack(DoublyLinkedNode<T>* node) for the class DoublyLinkedCircularList which will print out the elements in the list from back to front. The function is initially called with the first node in the list. You may not make use of the previous(prev) links
This is my solution where I got 2 out of a possible 3 marks:
template<class T>
void DoublyLinkedCircularList<T> :: printBack(DoublyLinkedNode<T>* node) {
if(node->next == NULL) //Correct- 1 mark
return 0;
else
printBack(node->next); //Correct - 1 mark
cout << current-> element << " ";
}
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Apr 1, 2014
I'm currently learning how to work with linked lists, specifically, doubly linked lists, and I have come across a problem with my program when I attempt to print it backwards. Here is the portion of the code :
#include <iostream>
using namespace std;
struct node {
int data; //int to store data in the list
node *next; //pointer to next value in list
node *prev; //pointer to previous value in list
[Code] ....
The purpose of this program is to create a list, print it forwards, backwards, insert an element, erase an element, and then destroy the list. I have chopped it down to just the create, print forward, and print backward functions.
The issue I have is that in the createList function I am modifying both begin and end but I can only return one or the other. This means that whichever I don't return is still NULL in the main function and therefore does not point to anything. I've tried setting the begin/current/end to not equal NULL but createList won't work if I do that.
How I could modify both? Just to be clear, the list HAS TO be created in a function, it would be very easy to just initialize it in the main...
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Apr 10, 2013
I would like to add a new function to my class, "reverse" that would reverse the order of the list. I have added a prototype in the "public:" section of the code (see the comment with PROTOTYPE in it). Your task is to complete the implementation (see the comment with IMPLEMENTATION in it. See the main() function to see how the results should look
#include
#include
using namespace std;
class List {
public:
// Constructs an empty list
List();
[Code]....
I cant seem to get the right function to put into reverse I have tried everything Im not sure where to start!
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Apr 29, 2013
I'm trying to write a function that takes two linked lists and creates a third one with only the common elements.
It assumes the first list (the caller) has no dups, but it doesn't seem to be working. The program doesn't crash, it just hangs when it is supposed to display L3 (the third list)..everything else runs and is displayed fine.
template <typename T>
LList <T> LList <T>:: common (LList <T> &B)//common fct
{
Node <T> *hunter1 = Head;
[Code]......
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Apr 6, 2013
1. Construct a class diagram that can be used to represent food items. A type of food can be classified as basic or prepared. Basic food items can be further classified as meat, fruit, veg or Grain. The services provide by the class should be the ability to enter data for new food, to change data for food and to display existing data about food.
using this class definition write a main program to include a simple menu that offers the following choices:
1. Add food
2. Modify Food
3. Delete Food
4. Exit this menu
2. Read a list of numbers from a file and then print them out in reverse order. State whether the list is palindromic or not.
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Jun 29, 2013
I have a linked list comprised of chars like so...
Code:
node1 - "p"
node2 - "o"
node3 - "p"
I need a function that will take in three perameters...node *replaceChar(node *head, char key, char *str)Stipulations of this function. head is the head of the list, 'key' and 'str' are guaranteed to contain alphanumeric characters only (A-Z, a-z, and 0-9). str can range from 1 to 1023 characters (inclusively). So if I call this function with these perameters..
Code:
node *head == /*the head of the list to be examined*/
char key == "p"char *str == "dog"The new list will look like this...
node1 - 'd'
node2 - 'o'
node3 - 'g'
node4 - 'o'
node5 - 'd'
node6 - 'o'
node7 - 'g'
All instances of 'p' were replaced with 'dog' I have a toString function which takes in a string and converts it to a linked list and returns the head. So assume that you can call the function on str = "dog" so...
Code:
toString(str) == /*this will return the head to the list made from the str*/
If it's unclear what my question is...I am stumped on how to write the replaceChar function the one that takes in three perameters..
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Dec 31, 2014
Code:
// Write a function called insertEntry() to insert a new entry into a linked list.
Have the procedure take as arguments a pointer to the list entry to be inserted (of type struct entry as defined in this chapter), and a pointer to an element in the list after which the new entry is to be inserted.
// The function dveloped in exercise 2 only inserts an element after an existing element in the list, thereby prenting you from inserting a new entry at the front of the list.
(Hint: Think about setting up a special structure to point to the beginning of the list.)
#include <stdio.h
struct entry1 {
int value;
struct entry1 *next;
};
[code]...
This is a working version of the exercise, but I don't think I'm doing what's asked. I was able to add an element to the beginning of the list using an if statement, not creating a special structure that points to the beginning of the list. How would I go about creating a special structure that points to the beginning of the list to add a new element at the beginning of the list?
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May 30, 2013
I'm working on a linked list and was wondering how this looks to everybody else for a deleteList function.
void deleteList(Node* head)
{
Node* iterator = head;
while (iterator != 0)
[code].....
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May 15, 2013
I need to make the functions using these function prototypes. I am mainly having problems with GetFirst() and SwapData() but how to do it..
Header File with Prototypes
Code:
#ifndef LINKEDLIST_H
#define LINKEDLIST_H
/**
* @file
* This file provided a doubly-linked list implementation capable of storing any arbitrary data.
* The list implementation relies on a chain metaphor: a list is merely a sequence of links
* (ListItems) and there is no separate construct to represent the entire list, each ListItem in it
[Code]....
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May 7, 2013
I read an article on linked list here: C Linked List Data Structure Explained with an Example C Program
Code:
struct test_struct* search_in_list(int val, struct test_struct **prev)
{
struct test_struct *ptr = head;
struct test_struct *tmp = NULL;
bool found = false;
}
[code].....
What is "if(prev)"? Wouldn't "prev" always have the same value? Secondly, if tmp is NULL (which will be the case when the loop if(ptr->val == val) finds a match the first time it is run), is *prev assigned a NULL?
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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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Jan 6, 2014
I have the codes for the functions: "Given the functions that we have discussed and defined in the class and the code that we have created, create the code for the Delete Node function and the Search function. Create an application that will incorporate all the functions that we have discussed and the new ones that you need to create. The application should allow the linked list to be built initially from a text file. The application should then allow for the user select an operation to perform. The acceptable operations are
- to search for an item
- to delete an item
- to enter a new item
- to exit the application
After the initial build and loading of data from the textfile, the application should print a listing of each item in the list and the node that it is located in. after a delete or insert, the application should display an output of the list again showing each item in the list and the node that it resides in.
The data item for this problem will be the inventory structure that we created in class and the data is in the inventory file that you already have downloaded."
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Mar 7, 2013
I am having difficulty getting my program to run. I have looked and looked many times trying to figure out what I am doing wrong. I have a hunch that it's my load function that's acting up, but from my perspective, my creation of my singly linked list looks good. From the creation of my singly linked list, does anything stand out as being abnormal?
Code:
typedef struct Node {
char word[LENGTH+1];
struct Node *Next;
} Node;
}
[code]....
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Apr 2, 2013
I been ask to create a sorted linked list module, and to test each function with 1 unit, 2 +.so i wrote my addtofront function( we have to use the same as the teacher)
Code:
struct MyList{
char * name;
Sorted * AddmyChar;
struct MyList * next;
}
[code]....
but i cant seem to test it because it always display a seg fault.... i dont know what i did wrong....how do i call this function in main to display a string i want?
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May 27, 2014
I decided to make a linked list program using classes and templates.I implemented my linked list and added some basic functions, everything worked just fine. Then I proceeded to add templates...First, the error list:
#pragma once
template<class T>
class Node {
private:
Node* next;
[code]....
To sum up: Something's wrong with the templates that I used in "List.cpp" and what it could be.
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Jan 2, 2013
My program is almost done all that is left is entering big numbers, the program can add and subtract small numbers but not big numbers because it puts them all in one node, I need the program to store each number in a node.
#include<iostream>
#include<string>
using namespace std;
class Node {
public:
int value;
Node * next;
[Code] .....
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Mar 30, 2013
When I am traversing a linked list ...i suppose we can do it only with pointers
like p is a head node pointer then
p
p->next
p->next->next
p-next->next->next
so on represents a link...
if i have to pass head node as struct variable itself...can i traverse a link using dot operator??
p and p.next and how to retrieve third and remaining links through this method if we can traverse like this???
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Mar 3, 2014
I have created this program to merge two linked list into one ,but however everything is working fine but on execution it providing a segmentation fault error ( on calling merging function )
code :
#include<iostream>
#include<stdio.h>
using namespace std;
struct node{
int data;
node* link;
[code].....
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Apr 1, 2013
I am unable to make any logical algorithm to access middle of stack. I am using stack implemented with linkedlists, I have following functions available for stack like push,pop,top.
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Sep 22, 2013
I had ...
class List;
List *deletezeroendlist(List* L);
class List {
public:
intdigit;
List*nextDigit;
public:
List():digit(0), nextDigit(NULL){}
List(int d, List *next):digit(d), nextDigit(next){}
I have tried many different ways but it is still not the answer / perform the function List *deletezeroendlist(List* L)
EX
L=12345600 -> L=123456
or L=01203000 -> L=01203
remove the 0 at the end
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Sep 12, 2013
Code is:
#include<stdio.h>
struct node {
int info;
struct node *next,*prev;
[Code] ....
How to reverse a linked list .....
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