prog_wait.cpp

#include <iostream>
using namespace std;

// A linked list node
struct Node
{
  double bla[20000];
  int data;
  struct Node *next;
};
//insert a new node in front of the list
void
push (struct Node **head, int node_data)
{
  /* 1. create and allocate node */
  struct Node *newNode = new Node;

  /* 2. assign data to node */
  newNode->data = node_data;

  /* 3. set next of new node as head */
  newNode->next = (*head);

  /* 4. move the head to point to the new node */
  (*head) = newNode;
}

//insert new node after a given node
void
insertAfter (struct Node *prev_node, int node_data)
{
  /*1. check if the given prev_node is NULL */
  if (prev_node == NULL)
    {
      cout << "the given previous node is required,cannot be NULL";
      return;
    }

  /* 2. create and allocate new node */
  struct Node *newNode = new Node;

  /* 3. assign data to the node */
  newNode->data = node_data;

  /* 4. Make next of new node as next of prev_node */
  newNode->next = prev_node->next;

  /* 5. move the next of prev_node as new_node */
  prev_node->next = newNode;
}

/* insert new node at the end of the linked list */
void
append (struct Node **head, int node_data)
{
/* 1. create and allocate node */
  struct Node *newNode = new Node;

  struct Node *last = *head;	/* used in step 5 */

/* 2. assign data to the node */
  newNode->data = node_data;

/* 3. set next pointer of new node to null as its the last node*/
  newNode->next = NULL;

/* 4. if list is empty, new node becomes first node */
  if (*head == NULL)
    {
      *head = newNode;
      return;
    }

/* 5. Else traverse till the last node */
  while (last->next != NULL)
    last = last->next;

/* 6. Change the next of last node */
  last->next = newNode;
  return;
}

// display linked list contents
void
displayList (struct Node *node)
{
  //traverse the list to display each node
  while (node != NULL)
    {
      //    cout<<node->data<<"-->";
      node = node->next;
    }

}

/* main program for linked list*/
int
main ()
{
/* empty list */
  struct Node *head = NULL;

// Insert 10.
  append (&head, 10);
  
 // getchar();

// Insert 20 at the beginning. 
  push (&head, 20);

// Insert 30 at the beginning. 
  push (&head, 30);

// Insert 40 at the end. 
  append (&head, 40);		// 
  // Insert 50, after 20. 
  insertAfter (head->next, 50);

//cout<<"Final linked list: "<<endl;
  displayList (head);

  getchar();
  //pause();

  return 0;
}