Question

using C++, NOT C language

1. Write a function called insert() to insert a node to the beginning of a linked list. The data is passed into the function. For example insert(8) will insert a node at the beginning of the list with the number 8 in the data field. Each node in the linked list is a ListNode struct as discussed in class.

2. Write a function called print() that will traverse the entire linked list and print out the data for all of the nodes.

3. Write a function to delete a node from the linked list. The node to delete is passed into the function. For example a call to delete(5) will delete the fifth node in the list. The function returns true if the delete operation is performed successfully, otherwise it returns false.

3. In the main program, call the insert function 10 times to create a linked list with 10 nodes. Call print() to make sure the list is created successfully. Ask the user to enter a node number to delete. Call delete(node_number) to delete the node.

Answer 1

// header files

#include <iostream>

using namespace std;

// define class

class LinkedList

{

protected:

  // declare structure for the list

  struct ListNode

  {

    // declare value in node

    double value;

    // point to the next node

    ListNode *next;

    ListNode(double value = 0, ListNode *next = NULL)

    {

      this->value = value;

      this->next = next;

    }

  };

  // list head pointer

  ListNode *head;

public:

  // linked list operations

  void insert(double num);

  void printNode();

  void deleteNode(int pos);

  bool memberOf(double x);

  LinkedList(const LinkedList &);

  ~LinkedList();

  LinkedList()

  {

    head = NULL;

  }

};

// copy constuctor

LinkedList::LinkedList(const LinkedList & otherList)

{

  head = NULL;

  // point to new node

  ListNode *newNode;

  // to move through in other list

  ListNode *nodePtr;

  // to move through developing list

  ListNode *tempPtr;

  // validate that other list is empty

  if (!otherList.head)

    return;

  // let nodePtr point to the list to be copied

  nodePtr = otherList.head;

  // allocate a new node anod store

  head = new ListNode();

  head->value = nodePtr->value;

  head->next = NULL;

  // move onto next mode in the list to be copied

  nodePtr = nodePtr->next;

  // let tempPtr point to the list to be developed

  tempPtr = head;

  // copy the remaining list

  while (nodePtr != NULL)

  {

    newNode = new ListNode;

    newNode->value = nodePtr->value;

    newNode->next = NULL;

    tempPtr->next = newNode;

    tempPtr = newNode;

    nodePtr = nodePtr->next;

  }

}

// add a new element to the end of the list

void LinkedList::insert(double number)

{

  if (head == NULL)

    head = new ListNode(number);

  else

  {

    // list is not empty

    ListNode *nodePtr = head;

    //appendNode new node to the head of the list

    head = new ListNode(number, nodePtr);

  }

}

// printNode outputs a sequence of all values

void LinkedList::printNode()

{

  ListNode *nodePtr = head;

  cout << "List: ";

  if (head == NULL)

  {

    cout << "List is empty" << endl;

  }

  while (nodePtr)

  {

    // printNode value in current node

    cout << nodePtr->value << " ";

    nodePtr = nodePtr->next;

  }

}

// destrtor deallocates the memory used by the list.

LinkedList::~LinkedList()

{

  ListNode *nodePtr = head;

  while (nodePtr != NULL)

  {

    // keep track of node to be deleted

    ListNode *garbage = nodePtr;

    // move on to next node

    nodePtr = nodePtr->next;

    // delete the garbage node

    delete garbage;

  }

}

// remove method

void LinkedList::deleteNode(int pos)

{

  // to move through the list

  ListNode *nodePtr;

  // to point to the previous node

  ListNode *previousNode;

  int i = 1;

  // condition if list is empty

  if (!head)

  {

    cout << "\nERROR: Cannot delete, list is empty";

    return;

  }

  // position nodePtr at the head of list

  nodePtr = head;

  // to insert at first

  if (pos == 1)

  {

    nodePtr = head->next;

    delete head;

    head = nodePtr;

  }

  else

  {

    while (nodePtr != NULL && i < pos)

    {

      previousNode = nodePtr;

      nodePtr = nodePtr->next;

      i++;

    }

    if (nodePtr)

    {

      previousNode->next = nodePtr->next;

      delete nodePtr;

    }

    else

      cout << "\nFailed to delete position " << pos << " not found";

  }

  nodePtr = head;

  while (nodePtr)

  {

    // display the value in the node

    cout << nodePtr->value << " -> ";

    //move to the next node

    nodePtr = nodePtr->next;

  }

  cout << "Null";

}

// main function

int main()

{

  // declare a variable of chain list

  LinkedList info;

for(int i = 1; i<=10 ; ++i)

info.insert(i*i);

  info.printNode();

  double x;

  int pos;

  cout << "\nPlease enter element position to be deleted: ";

  cin >> pos;

  info.deleteNode(pos);

  return 0;

}

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SEE OUTPUT


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