C++ || Snippet – Simple Linked List Using Delete, Insert, & Display Functions

August 18, 2012 admin No comments

The following is sample code for a simple linked list, which implements the following functions: “Delete, Insert, and Display.”

The sample code provided on this page is a stripped down version of a more robust linked list class which was previously discussed on this site. Sample code for that can be found here.

It is recommended you check that out as the functions implemented within that class are very useful.





		
		
			Simple Linked List
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Aug 18, 2012
//    Taken From: http://programmingnotes.org/
//    File:  SimpleList.cpp
//    Description: Demonstrates the use of a simple linked list.
// ============================================================================
#include <iostream>
#include <string>
using namespace std;

struct node
{
    /* -- you can use different data types here
         -- instead of just a string
    char letter;
    int number;
    double fNumber;
    */
    string name;
    node* next;
};

// global variables
// this is the front of the list
node* head = NULL;

// function prototype
void Insert(string info);
void Delete(string info);
void Display();
void DestroyList();

int main()
{
    // if you want to insert data into the list
    // this is one way you can do it, using a 'temp' pointer
    node* temp = new node;
    temp->name = "My Programming Notes";
    temp->next = NULL;

    // set the head node to the data thats in the 'temp' pointer
    head = temp;

    // display data to the screen
    cout << head->name <<endl<<endl;

    // use the insert function to add new data to the list
    // NOTE: you could have also used the 'insert' function ^ above
    // to place data into the list
    Insert("Is An Awesome Site!");

    // insert more data into the list
    Insert("August");
    Display();

    // delete the selected text from the list
    Delete("August");
    Display();

    // destroy the current pointers in the list
    // after you are finished using them
    DestroyList();

    return 0;
}// end of main

void Insert(string info)
{
    node* newItem = new node;
    newItem->name = info;
    newItem->next = NULL;

    // if the list is empty, add new item to the front
    if(head == NULL)
    {
        head = newItem;
    }
    else // if the list isnt empty, add new item to the end
    {
        node* iter = head;
        while(iter->next != NULL)
        {
            iter = iter->next;
        }
        iter->next = newItem;
    }
}// end of Insert

void Delete(string info)
{
    node* iter = head;

    // if the list is empty, do nothing
    if(head == NULL)
    {
        return;
    }
    // delete the first item in the list
    else if(head->name == info)
    {
        head = head->next;
        delete iter;
    }
    // search the list until we find the desired item
    else
    {
        while(iter->next != NULL)
        {
            if(iter->next->name == info)
            {
                node* deleteNode = iter->next;
                iter->next = iter->next->next;
                delete deleteNode;
                break;
            }
            iter = iter->next;
        }
    }
}// end of Delete

void Display()
{
    node* iter = head;
    // traverse thru the list, displaying the
    // text at each node location
    while(iter != NULL)
    {
        cout<<iter->name<<endl;
        iter = iter->next;
    }
    cout<<endl;
}// end of Display

void DestroyList()
{
    if(head != NULL)
    {
        cout << "\n\nDestroying nodes...\n";
        while(head != NULL)
        {
            node* temp = head;
            cout << temp->name <<endl;
            head = head->next;
            delete temp;
        }
    }
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Aug 18, 2012
//    Taken From: http://programmingnotes.org/
//    File:  SimpleList.cpp
//    Description: Demonstrates the use of a simple linked list.
// ============================================================================
#include <iostream>
#include <string>
using namespace std;
 
struct node
{
    /* -- you can use different data types here
         -- instead of just a string
    char letter;
    int number;
    double fNumber;
    */
    string name;
    node* next;
};
 
// global variables
// this is the front of the list
node* head = NULL;
 
// function prototype
void Insert(string info);
void Delete(string info);
void Display();
void DestroyList();
 
int main()
{
    // if you want to insert data into the list
    // this is one way you can do it, using a 'temp' pointer
    node* temp = new node;
    temp->name = "My Programming Notes";
    temp->next = NULL;
 
    // set the head node to the data thats in the 'temp' pointer
    head = temp;
 
    // display data to the screen
    cout << head->name <<endl<<endl;
 
    // use the insert function to add new data to the list
    // NOTE: you could have also used the 'insert' function ^ above
    // to place data into the list
    Insert("Is An Awesome Site!");
 
    // insert more data into the list
    Insert("August");
    Display();
 
    // delete the selected text from the list
    Delete("August");
    Display();
 
    // destroy the current pointers in the list
    // after you are finished using them
    DestroyList();
 
    return 0;
}// end of main
 
void Insert(string info)
{
    node* newItem = new node;
    newItem->name = info;
    newItem->next = NULL;
 
    // if the list is empty, add new item to the front
    if(head == NULL)
    {
        head = newItem;
    }
    else // if the list isnt empty, add new item to the end
    {
        node* iter = head;
        while(iter->next != NULL)
        {
            iter = iter->next;
        }
        iter->next = newItem;
    }
}// end of Insert
 
void Delete(string info)
{
    node* iter = head;
 
    // if the list is empty, do nothing
    if(head == NULL)
    {
        return;
    }
    // delete the first item in the list
    else if(head->name == info)
    {
        head = head->next;
        delete iter;
    }
    // search the list until we find the desired item
    else
    {
        while(iter->next != NULL)
        {
            if(iter->next->name == info)
            {
                node* deleteNode = iter->next;
                iter->next = iter->next->next;
                delete deleteNode;
                break;
            }
            iter = iter->next;
        }
    }
}// end of Delete
 
void Display()
{
    node* iter = head;
    // traverse thru the list, displaying the
    // text at each node location
    while(iter != NULL)
    {
        cout<<iter->name<<endl;
        iter = iter->next;
    }
    cout<<endl;
}// end of Display
 
void DestroyList()
{
    if(head != NULL)
    {
        cout << "\n\nDestroying nodes...\n";
        while(head != NULL)
        {
            node* temp = head;
            cout << temp->name <<endl;
            head = head->next;
            delete temp;
        }
    }
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output

My Programming Notes
My Programming Notes Is An Awesome Site! August [DELETE THE TEXT "AUGUST"] My Programming Notes Is An Awesome Site!
Destroying nodes... My Programming Notes Is An Awesome Site!

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Posted in: Advanced, C++, C++, Snippets Tags: c++, if/else, linked list, While Loop

C++ || Snippet – Simple Linked List Using Delete, Insert, & Display Functions

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