Chapter 13.1, Problem 4STE

Program Plan Intro

Linked list:

• Linked list denotes a linear data structure.
• The elements are not stored at contiguous locations; the elements are linked using pointers.
• It stores linear data of similar types not like arrays.
• The size of linked list can be changed based on requirement.
• It is represented by a pointer to first linked list node.
• The first node denotes a head.
• If linked list is empty, value of head is NULL.
• The node in a list has two parts, data and pointer to next node.

Given code:

//Define a structure

struct ListNode

{

//Declare variable

string item;

//Declare variable

int count;

//Define next node

ListNode *link;

};

//Create instance

ListNode *head = new ListNode;

Explanation:

• The “ListNode” defines a structure with “item” and “count” as members.
• It has a pointer “link” to next element of list.
• The “ListNode *head = new ListNode” creates an instance of structure and a new element is created.

Complete program:

//Include libraries

#include<iostream>

#include<string>

//Use namespace

using namespace std;

//Define a structure

struct ListNode

{

//Declare variable

string item;

//Declare variable

int count;

//Define next node

ListNode *link;

};

//Create instance

ListNode *head = new ListNode;

//Define main method

void main()

{

//Assign value

head->item = "Wilbur's brother Orville";

//Display value

cout << head->item << endl;

//Pause console window

system("pause");

}

Explanation:

• The “ListNode” defines a structure with “item” and “count” as members.
• It contains a pointer “link” to next element of list.
• The “ListNode *head = new ListNode” creates an instance of structure and a new element is created.
• The main method assigns value to “item” to head of linked list.
• The value of head of linked list is been displayed.