Create a reverse LinkedList in C from a given LinkedList

0 votes

I'm having some problems making a linkedlist from a provided linkedlist in reverse order.

I have a background in java and have just begun working with C++.

Could you go at my code and let me know what's wrong? 

I anticipate that all I'm doing is changing the cursor, not producing anything new.

//this is a method of linkedlist class, it creates a reverse linkedlist
//and prints it

void LinkedList::reversedLinkedList()
{
    Node* revHead;

    //check if the regular list is empty
    if(head == NULL)
       return;

    //else start reversing
    Node* current = head;
    while(current != NULL)
    {
        //check if it's the first one being added
        if(revHead == NULL)
           revHead = current;

        else
        {
            //just insert at the beginning
            Node* tempHead = revHead;
            current->next = tempHead;
            revHead = current;
        }
        current = current->next;

     }//end while

     //now print it
     cout << "Reversed LinkedList: " << endl;

     Node* temp = revHead;
     while(temp != NULL)
     {
         cout << temp->firstName << endl;
         cout << temp->lastName << endl;
         cout << endl;

         temp = temp->next;
      }

}//end method
Aug 3, 2022 in C++ by Nicholas
• 7,760 points
766 views

1 answer to this question.

0 votes

A simpler solution is to just let the current node point to the previous node while going through your linked list, saving the previous and next nodes as you go.

void LinkedList::reversedLinkedList()
{
    if(head == NULL) return;

    Node *prev = NULL, *current = NULL, *next = NULL;
    current = head;
    while(current != NULL){
        next = current->next;
        current->next = prev;
        prev = current;
        current = next;
    }
    // now let the head point at the last node (prev)
    head = prev;
}
answered Aug 5, 2022 by Damon
• 4,960 points

Related Questions In C++

0 votes
0 answers

Reverse a number without converting it to string in C++

I'm attempting to write a programme in C++ to reverse a number. It works well with numbers like 1234, but when I try to enter a number like 5430, it displays 345, and the same with numbers that begin with zero, such as 0234, which displays 432. Could someone please explain how to deal with zeros at the beginning and end of a sentence? I simply need to save the number without converting it to a string. #include<iostream> using namespace std; int main(){ ...READ MORE

Jun 30, 2022 in C++ by Nicholas
• 7,760 points
601 views
0 votes
0 answers

How to find if a given key exists in a C++ std::map

I'm trying to check if a given ...READ MORE

Jul 14, 2022 in C++ by Nicholas
• 7,760 points
768 views
0 votes
1 answer

How to reverse a number in C++?

#include <iostream> using namespace std; int main() { int n; cin>>n; int ...READ MORE

answered Oct 28 in C++ by kavya
77 views
0 votes
1 answer

What is a lambda expression in C++11?

In C++11, what is a lambda expression? A: It's the object of an autogenerated class with overloading operator() const under the hood.  Closure is a type of object that is produced by the compiler.  This 'closure' idea is similar to C++11's bind notion.  Lambdas, on the other hand, usually produce better code.  Full inlining is also possible with calls through closures. Q: When do you think I'd utilise one? A: Define "simple and tiny logic" and request that the compiler generate the code from the preceding question.  You tell the compiler the expressions you wish to be inside the operator ().  The compiler will produce everything else for you. Q: What kind of problem do they tackle that couldn't be solved before they were introduced? A: It's some form of syntactic sugar, like using operators instead of functions for custom add, subtract, and other operations... However, wrapping 1-3 lines of genuine logic to some classes, and so on, saves additional lines of needless code!  Some engineers believe that if the number of lines is reduced, there is a lower likelihood of mistakes (which I agree with). Example of usage auto x = [=](int arg1){printf("%i", ...READ MORE

answered Jun 15, 2022 in C++ by Damon
• 4,960 points
457 views
0 votes
1 answer

Simple linked list in C++

This is the most basic example I can think of in this situation, and it has not been tested.  Please keep in mind that this violates some C++ best practises and deviates from the norm (initialize lists, separation of declaration and definition, and so on).  But those aren't topics I can discuss here. #include <iostream> using namespace std; class LinkedList{ ...READ MORE

answered Jun 2, 2022 in C++ by Damon
• 4,960 points
863 views
0 votes
1 answer

C++ "Object" class

No, there is no generic base class&nb ...READ MORE

answered Jun 2, 2022 in C++ by Damon
• 4,960 points
497 views
0 votes
1 answer

setuptools: build shared libary from C++ code, then build Cython wrapper linked to shared libary

There is a seemingly undocumented feature of setup that ...READ MORE

answered Sep 11, 2018 in Python by Priyaj
• 58,020 points
686 views
0 votes
1 answer

setuptools: build shared libary from C++ code, then build Cython wrapper linked to shared libary

There is a seemingly undocumented feature of setup that ...READ MORE

answered Sep 21, 2018 in Python by Priyaj
• 58,020 points
2,384 views
0 votes
1 answer

In C++, what is a virtual base class?

When employing multiple inheritance, virtual base classes are used to prevent several "instances" of a particular class from appearing in an inheritance hierarchy. Consider the following example: class A { public: void Foo() {} ...READ MORE

answered Jun 10, 2022 in C++ by Damon
• 4,960 points
515 views
0 votes
1 answer

What is the best way to use a HashMap in C++?

The ordered and unordered map containers (std::map and std::unordered map) are included in the standard library.  The items in an ordered map are sorted by key, and insert and access are in O (log n).  For ordered maps, the standard library often use red black trees.  However, this is only an implementation detail.  Insert and access are in O in an unordered map (1).  It is simply another term for a hashtable. An illustration using (ordered) std::map: #include <map> #include <iostream> #include <cassert> int main(int argc, char ...READ MORE

answered Jun 10, 2022 in C++ by Damon
• 4,960 points
830 views
webinar REGISTER FOR FREE WEBINAR X
REGISTER NOW
webinar_success Thank you for registering Join Edureka Meetup community for 100+ Free Webinars each month JOIN MEETUP GROUP