CODEWITHSUNDEEP
c++algorithmlinked-list
Jule Hc
Jule Hc

Reputation: 19

Adding a new value into the linked list

I'm trying to implement function in linked list which will add a new note. That new node is a sum of a previous and next node.

Here is my code, but i don't know where is mistake.

void change(Node *head){

    Node *p = head;
    Node *temp = new Node;
    temp->next = NULL;

    while(p != NULL){
        temp->data = p->data + p->next->data;
        temp->next = p->next;
        p->next = temp;
        p = p->next;
    }   
}

Upvotes: 0

Views: 40

Answers (2)

eerorika
eerorika

Reputation: 238411

If head is null, then this function allocates a new Node, but nothing points to the new node, so it will be leaked.

If head isn't null, but is the last (i.e. the only) node of the list, then p->next->data indirects through the null pointer, and the behaviour of the program is undefined.

Otherwise, in the first iteration, p->next = temp; p = p->next; makes p be the same as temp, and in the second iteration p->next = temp; makes the node point to itself, and the loop will never terminate.

Upvotes: 2

user2618142
user2618142

Reputation: 1065

If I have understood the problem correctly after reviewing the code, the changes made do not persist after the function call.

void change(Node *head ){

to

void change(Node *& head ){

Pls try this.

Edit:-

There are other problems in the code as pointed out by others like
1. Dereferencing a null pointer
2. Invalid memory access.

Upvotes: 0

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