Thread: Creating a linked list using recursive function

Hi I am a beginner learning c++ I am trying to create a linked list using recursive function I though I got more or less pointer, linked list, data structure etc but I am stuck for 2 days.
Here's my entire code.
What I am basically trying to do is like I said creating a linked list using only recursive function. The problem is my pointer variable 'head' is always pointing to NULL and I can't figure out why and i guess i misunderstood a lot of things but i simply don't know what ... and more i try more i am getting confused.
It must be quite newbie question but Id really appreciate if someone can help me.

Code:

 

#include

Code:

<iostream>

usingnamespace std;

struct linkedlist
{
    int value;
    linkedlist *next;
};

void insertNode(linkedlist* temp)
{
    if(temp->next != NULL)
    {
        insertNode(temp->next);
    }
    else
    {
        temp->next =new linkedlist;
        temp->next->value =0;
        temp->next->next = NULL;
    }

}


linkedlist *addNode(linkedlist *temp)
{ 
    if(temp == NULL)
    {
        linkedlist *newelement =new linkedlist;
        newelement->value =0;
        newelement->next = NULL;
        temp = newelement;

        return newelement;
    }
    else
    {
        insertNode(temp);
    }
}

void displaylist(linkedlist *temp)
{
    while(temp != NULL)
    {
        cout << temp->value << endl;
        temp = temp->next;
    }
}

int main()
{
    linkedlist *head = NULL;

    linkedlist *element1 = addNode(head);
    linkedlist *element2 = addNode(head);
    linkedlist *element3 = addNode(head);
    linkedlist *element4 = addNode(head);
    linkedlist *element5 = addNode(head);

    cin.ignore();
    cin.get();
}

I am not a C++ programmer, but since your code seems pretty "C-like", I'll just point out the problem I see.

You pass the "head" pointer to "addnode()" and try to update it, but any changes are local only to that function (i.e. not seen in "main()"). In order to update this variable in the calling function, you need to pass a pointer to that variable (in this case, a pointer to a pointer).

There are other issues in the code (e.g. creating discrete variables "element 1" etc defeats the purpose of a linked list), but hopefully this should get you set on the right path.

If you want another nice linked list exercise try radioactive mutant vampire bunnies.Beginner Exercises - C++ Forum