Get Nth node in a linked list

Hi there. I'm back :-)

Code:

---

void GetNth (node** head)
{
        node* current = *head;
        node* walker = *head;
        int n, length, count;
       
        printf("Input n ...  ");
        scanf("%d",n);
       
        length = 0;
        count = 0;
        if (current == NULL)
        {
                length = 0;
        }
        else
        {
                while (current != NULL)
                {
                        length++;
                        current = current->next;
                }               
        }
       
        if (n>length)
        {
                printf("\nNo such Node\n");
        }
        else
        {
                do 
                {
                        walker = walker->next;
                        count++;
                } while (count != n);
                       
                /* found the Nth*/       
                printf("N-th => NAME: %s\tAGE: %d\n",walker->name,walker->age);
               
                }
        }

}

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this doesn't work no matter which number I enter for n, and no matter how long the list is. can you help me?

scanf("%d",n) should be scanf("%d", &n). However, consider what happens if the user enters a negative number.

Incidentally, I do not think that you need to get the length of the linked list. You can begin traversing over it straight away, and if you find that you have reached the end of the linked list without reaching the nth node, then clearly there is no such node.

do you mind giving me a little help with that algorithm?

You've done it already.

Quote:

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Originally Posted by MK27

You've done it already.

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No, since what budala implemented involves first finding the length of the linked list, and then if tghe desired index does not exceed the length, traverse over the linked list to find the desired node.

Quote:

---

Originally Posted by budala

do you mind giving me a little help with that algorithm?

---

Sure. Firstly, I suggest that you separate the finding of the nth node from its use. That is, create another function that returns a pointer to the nth node, or a null pointer if no such node exists:

Code:

---

node *GetNthNode(node *head, int n);

---

If n is less than 0, return a null pointer. Otherwise, initialise the current node to point to the head (or you can reuse the pointer named head) and initialise a counter to 0. While the current node is not null and your counter is less than n, make the next node be the current node and increment the counter. Return the pointer to the current node when the loop ends.

Now, implementing GetNth() is easy: you just need to get the input from the user (which you have already done), call GetNthNode(), and depending on whether the return value is a null pointer you decide to either print the error message or print the node's contents.