Doubly_LinkedList.cpp

//============================================================================
// Name        : Doubly_LinkedList.cpp
// Author      : Mir Sahib
// Version     :
// Copyright   : MIT License
// Description : Doubly Linked List implementation
//============================================================================

#include <iostream>
#include "List.h"
using namespace std;


List::List(){
	head = NULL;
	temp = NULL;
	curr = NULL;
}
node *List::get(int index){
	temp = new node;
	if(index>size()){
		temp = NULL;
	}else{
		curr = head;
		for(int i=0;i<index-2;i++){
			curr=curr->next;
		}
		temp = curr->next;
	}
	return temp;
}
node *List::getFirst(){
	return head;
}
node *List::getLast(){
	temp = head;
	while(temp!=NULL){
		temp = temp->next;
	}
	return temp;
}

//insert function
void List::add(int index,int newData){
	if(index>size()){
		cout<<"Invalid Index"<<endl;
	}else{
		temp = new node;
		temp->data = newData;
		temp->prev = NULL;
		temp->next = NULL;

		curr = head;
		for(int i=0;i<index-2;i++){
			curr = curr->next;
		}
		temp->next = curr->next;
		temp->prev = curr;
		curr->next = temp;
	}
}
void List::addFirst(int newData){
    temp = new node;
    temp->data = newData;
    temp->prev = NULL;
    temp->next = NULL;
    if(isEmpty()){
        head = temp;
    }else{
        temp->next = head;
        head->prev = temp;
        head = temp;
    }


}
void List::addLast(int newData){
    temp = new node;
    temp->data = newData;
    temp->prev = NULL;
    temp->next = NULL;
    if(isEmpty()){
        head = temp;
    }else{
        curr = head;
        while(curr->next!=NULL){
            curr = curr->next;
        }
        curr->next = temp;
        temp->prev = curr;
    }
}
//delete function
void List::remove(int index){
	if(index>size()){
		cout<<"Invalid Index"<<endl;
	}else{
		curr = head;
		for(int i=0;i<index-2;i++){
			curr = curr->next;
		}
		temp = curr->next;
		curr->next = temp->next;
		temp->next->prev = curr;
		delete temp;
	}
}
void List::removeFirst(){
	if(!isEmpty()){
		curr = head;
		curr->next->prev=NULL;
		head = curr->next;
		delete curr;
	}else{
		cout<<"The List is empty"<<endl;
	}
}
void List::removeLast(){
	if(!isEmpty()){
		curr = head;
		while(curr->next!=NULL){
			curr=curr->next;
		}
		curr->prev->next=NULL;
		delete curr;
	}else{
		cout<<"The List is empty"<<endl;
	}
}
//print function
void List::print(){
    curr = head;
    cout<<"List is: ";
    while(curr!=NULL){
        cout<<curr->data<<" ";
        curr=curr->next;
    }
    cout<<endl;
}

//miscellaneous function
int List::size(){
	temp = head;
	int i=0;
	while(temp!=NULL){
		i++;
		temp = temp->next;
	}
	return i;

}
bool List::isEmpty(){
	if(head==NULL){
		return true;
	}
	return false;
}

int main() {
    List myList;
	int limit,num;
	cout<<"How many number to print"<<endl;
	cin>>limit;

	for(int i=0;i<limit;i++){
        cout<<"Enter number"<<endl;
        cin>>num;
        myList.addFirst(num);
        //myList.addLast(num);
        myList.print();
	}
	myList.addLast(14);
	myList.addLast(15);
	myList.addLast(16);
	myList.addLast(17);
	myList.print();
	cout<<"Adding element at index 4"<<endl;
	myList.add(4,56);
	myList.print();
	cout<<"Number at index 5 : "<<myList.get(5)->data<<endl;
	cout<<"Delete first"<<endl;
	myList.removeFirst();
	myList.print();
	cout<<"Delete Last"<<endl;
	myList.removeLast();
	myList.print();
	cout<<"Delete index 3: "<<endl;
	myList.remove(3);
	myList.print();

	return 0;
}