Question

1.      Write a function called deleteNode, which accepts a pointer to a list, and a pointer to the node to be deleted from the list, eg

a. void deleteNode(node *head, node *delNode );

2.      Write a function called insertNode, which accepts a pointer to a list, a pointer to a new node to be inserted, and a pointer to the node after which the insertion takes place, eg

a. void insertNode(node *head, node *newNode, node *prevNode );

Answer 1

Ques 1.

void deleteNode(node *head, node *delNode )

{

    // if list or the node to be deleted is empty

    if( !head || !delNode )

        return;

   

    node *trav = head;

   

    // go to the previous node to delNode

    // loop until the list ends

    // assuming next point to the next node

    // if there is a method that returns next, like getNext()

    // the use

    // trav->getNext() != NULL

    while( trav->next != NULL )

    {

        // assuming val stores the data element

        // if there is a method that returns next, like getVal()

        // the use

        // trav->getVal() != NULL

        //

        // assuming next point to the next node

        // if there is a method that returns next, like getNext()

        // the use

        // trav->getNext() != NULL

        if( trav->next->val == delNode->val )

        {

            // remove delNode

            trav->next = trav->next->next;

           

            // remove the memory of the node

            delete delNode;

           

            break;

        }

       

        // go to next node

        // assuming next point to the next node

        // if there is a method that returns next, like getNext()

        // the use

        // trav = trav->getNext()

        trav = trav->next;

    }

}

Ques 2.

void insertNode(node *head, node *newNode, node *prevNode )

{

    // if node i to be inserted at the beginning of the list

    if( !head || !prevNode )

    {

        // make newnode point to head of the list

        newNode->next = head;

       

        // make newNode as the new head

        head = newNode;

    }

    else

    {

        // adjust the pointers

        newNode->next = prevNode->next;

       

        prevNode->next = newNode;

    }

}