linkedlist.cpp

/* This file was first created on 18th August,2018 by Keshav Tangri
This is for educational purposes only.
This is for B.Tech Students who are or will be studying Data Structures in there curriculum
For queries mail me @ : tangri57@gmail.com
*/
#include<iostream>
#include<cstdlib>
#include<math.h>
using namespace std;

class Node{
public:
Node* next;
int data;
};

class llist{
public:
Node* head = new Node;
llist(){
head=NULL;
}
Node* createnode(int value); //line 114
void addatbeg(int val);//line 150
void display();//line 136
void addele(int val);//line 121
void addatpos(int val);//line 246
void deleteele(int pos);//line 157
void deletelist();//line 424
int searchele(int val);//line 191
void updateval(int val);//line 212
void reverselist();//line 278
void sortlist();//line 299
void display_nth_element(int pos);//line 322
void display_nth_element_from_last(int pos);//line 350
void palindrome_list();//line 365
void remove_duplicate_usorted_list();//line 398
void swap_nodes_without_swapping_values(int val1,int val2);
};
//MAIN FUNCTION BEGINS HERE !
int main(){
int value;
int posi=0;
llist obj;
while(1){
int i;
cout<<"1.Add element at first position\n2.Add element at last position\n3.Add element at a position\n4."
<<"Display List\n5.Delete Element\n6.Delete Whole List\n7.Search an Element\n8.Update Value\n9.Reverse the list\n10.Sort the List\n11.Display N-th Element\n"
                  <<"12.Display N-th Element From Last\n13.Palindrome Linked List\n14.Remove Duplicates\n15.Swap nodes without swapping values\n16.Exit\nChoose your option : ";
cin>>i;
switch(i){
case 1:
cout<<"Enter value you want to add : ";
cin>>value;
cout<<"\n";
obj.addatbeg(value);
break;
case 2:
cout<<"Enter value you want to add : ";
cin>>value;
cout<<"\n";
obj.addele(value);
break;
case 3:
cout<<"Enter value you want to add : ";
cin>>value;
obj.addatpos(value);
break;
case 4:
obj.display();
break;
case 5:
cout<<"Enter position where you want to delete : ";
cin>>value;
obj.deleteele(value);
break;
case 6:
obj.deletelist();
break;
case 7:
cout<<"Enter the value of element you want to search : ";
cin>>value;

posi=obj.searchele(value);
if(posi==0){
cout<<"\n\nELEMENT NOT FOUND !\n\n";
}else{
cout<<"\n\nElement found at : "<<posi<<" position.\n\n";
}
break;
case 8:
cout<<"Enter the value of the Element you want to update : ";
cin>>value;
obj.updateval(value);
break;
case 9:
obj.reverselist();
break;
case 10:
obj.sortlist();
break;
case 11:
cout<<"Enter Position of the Element : ";
cin>>value;
obj.display_nth_element(value);
break;
case 12:
cout<<"Enter Position of the Element from Last: ";
cin>>value;
obj.display_nth_element_from_last(value);
break;
case 13:
obj.palindrome_list();
break;
case 14:
obj.remove_duplicate_usorted_list();
break;
case 15:
cout<<"\n\nUNDER MAINTAINENCE\n\n";
int val2;
cout<<"Enter the value of 2 nodes you want to swap : ";
cin>>value;
cin>>val2;
obj.swap_nodes_without_swapping_values(value,val2);
break;
case 16:
exit(0);
break;
}
}

}
//CLASS FUNCTIONS BEGINS HERE !


//CREATING THE NODE !
Node* llist::createnode(int value){
Node* temp =new Node;
temp->data = value;
return temp;
}

//ADDING ELEMENT AT LAST !
void llist::addele(int val){

if(head == NULL){
    addatbeg(val);
}else{
Node* temp = createnode(val);
Node* ptr =head;
while(ptr->next!=NULL){
ptr=ptr->next;
}
temp->next=NULL;
ptr->next=temp;
}
}
//PRINTING THE LINKED LIST !
void llist::display(){
Node* ptr = head;
if(head==NULL){
cout<<"\nList does not exist !\n";
return;
}
while(ptr!=NULL){
cout<<ptr->data<<" ";
ptr = ptr->next;
}
cout<<"\n\n";
}

//ADD ELEMENT AT BEGINNING !
void llist::addatbeg(int val){
Node* temp = createnode(val);
temp->next = head;
head = temp;
}

//DELETE AT POSITION !
void llist::deleteele(int pos){
if(head == NULL){
cout<<"ERROR !\nLIST IS EMPTY !\n";
return;
}
if(pos==1){
Node* p = head;
head = p->next;
delete p;
cout<<"\nElement Deleted !\n";
}else{
int counter = 0;
Node* p = head;
while(p!=NULL){
p=p->next;
counter++;
}
if(pos>1&&pos<=counter){
p = head;
Node* prev;
for(int i=1;i<pos;i++){
prev =p;
p=p->next;
}
prev->next=p->next;
delete p;
cout<<"\nELEMENT DELETED SUCCESSFULLY !\n";
}else{
cout<<"\nOUT OF RANGE EXCEPTION !\n\n";
}
}
}

//SEARCHING AN ELEMENT FUNCTION !
int llist::searchele(int val){
int counter=0;
Node* p = head;
if(head==NULL){
cout<<"\nEMPTY LIST !\n";
return counter;
}
while(p!=NULL){
counter++;
if(p->data==val){
break;
}
p=p->next;
}
if(p==NULL){
counter = 0;
}
return counter;
}


//UPDATING A VALUE FUNCTION
void llist::updateval(int val){
int counter=0;
Node* p = head;
if(head==NULL){
cout<<"\nEMPTY LIST !\n";
return;
}
while(p!=NULL){
counter++;
if(p->data==val){
break;
}
p=p->next;
}
if(p==NULL){
cout<<"\nVALUE NOT PRESENT !\n";
return;
}
if(p!=NULL){
cout<<"Enter New Value to be updated : ";
int temp;
cin>>temp;
p->data = temp;
cout<<"\nVALUE UPDATED !\n\n";
}
}
//ADDING ELEMENT AT A POSITION !
void llist::addatpos(int val){
cout<<"Enter position where you want to add the element : ";
int pos;
cin>>pos;
Node* ptr = head;
int counter =0;
if(pos==1){
addatbeg(val);
cout<<"\n\nELEMENT ADDED SUCCESSFULLY !\n\n";
}else{
while(ptr!=NULL){
counter++;
ptr=ptr->next;
}
if(pos>1&&pos<=counter){
Node* prev;
Node* temp = createnode(val);
ptr = head;
for(int i =1;i<pos;i++){
    prev = ptr;
    ptr=ptr->next;
}
prev->next = temp;
temp->next = ptr;
cout<<"\n\nELEMENT ADDED SUCCESSFULLY !\n\n";
}else{
cout<<"\n\nEND OF RANGE EXCEPTION !\n\n";
return;
}
}
}

//REVERSING THE LIST FUNCTION
void llist::reverselist(){
if(head==NULL){
cout<<"\n\nEMPTY LIST !\n\n";
return;
}
Node* curr;
Node* prev;
curr = head;
head = head->next;
curr->next=NULL;
while(head->next!=NULL){
prev = curr;
curr = head;
head = head->next;
curr->next = prev;
}
head->next=curr;
cout<<"\n\nLIST REVERSED SUCCESSFULLY !\n\n";
}

//SORTING THE LIST FUNCTION !
void llist::sortlist(){
if(head==NULL){
cout<<"\n\nEMPTY LIST !\n\n";
return;
}else{
Node* ptr = head;
Node* s=ptr->next;
while(ptr!=NULL){
while(s!=NULL){
if(ptr->data>s->data){
int temp = ptr->data;
ptr->data=s->data;
s->data=temp;
}
s=s->next;
}
ptr=ptr->next;
s=ptr;
}
cout<<"\n\nLIST SORTED SUCCESSFULLY !\n\n";
}
}
//DISPLAY NTH ELEMENT IN A LINKED LIST FUNCTION
void llist::display_nth_element(int pos){
if(head ==NULL){
cout<<"\n\nEMPTY LIST\n\n";
return;
}
if(pos==1){
cout<<"\n\nValue at "<<pos<<" is : "<<head->data<<"\n\n";
return;
}else{
Node* ptr = head;
int counter=0;
while(ptr!=NULL){
counter++;
ptr=ptr->next;
}
if(pos>=counter){
cout<<"\n\nOUT OF RANGE EXCEPTION !\n\n";
return;
}else{
ptr = head;
for(int i=1;i<pos;i++){
    ptr=ptr->next;
}
cout<<"\n\nValue at required position is : "<<ptr->data<<"\n\n";
}
}
}
//DISPLAY NTH ELEMENT FROM LAST IN A LINKED LIST function
void llist::display_nth_element_from_last(int pos){
if(head ==NULL){
cout<<"\n\nEMPTY LIST\n\n";
return;
}
Node* ptr = head;
int counter=0;
while(ptr!=NULL){
counter++;
ptr=ptr->next;
}
pos = counter-pos+1;
display_nth_element(pos);
}
//PALINDROME LINKED LIST FUNCTION !
void llist::palindrome_list(){
if(head==NULL){
cout<<"\n\nEMPTY LIST !\n\n";
return;
}
Node* ptr = head;
int counter=0;
while(ptr!=NULL){
counter++;
ptr=ptr->next;
}
ptr = head;
llist ob2;
for(int i=0;i<counter;i++){
ob2.addatbeg(ptr->data);
ptr = ptr->next;
}
ptr = head;
Node* ptrnew = ob2.head;
bool flag = true;

for(int i=0;i<counter;i++){

if(ptr->data!=ptrnew->data){
    flag = false;
    break;
}
ptr=ptr->next;
ptrnew=ptrnew->next;
}
if(flag){
cout<<"\n\nLinked List is a Palindrome !\n\n";
}else{
cout<<"\n\nLinked List is not a Palindrome !\n\n";
}
}
//REMOVING DUPLICATES FROM LIST
void llist::remove_duplicate_usorted_list(){
if(head==NULL){
cout<<"\n\nEMPTY LIST !\n\n";
return;
}
Node* ptr =head;
Node* prev;
Node* nextptr;
while(ptr!=NULL){
prev = ptr;
nextptr = ptr->next;
while(nextptr!=NULL){
    if(nextptr->data==ptr->data){
        prev->next=nextptr->next;
        delete nextptr;
        nextptr = prev->next;
    }else{
    prev = nextptr;
    nextptr = nextptr->next;
    }
}
ptr = ptr->next;
}
cout<<"\n\nDUPLICATES REMOVED SUCCESSFULLY !\n\n";
}
//DELETE WHOLE LIST FUNCTION
void llist::deletelist(){
if(head==NULL){
cout<<"\n\nEMPTY LIST !\n\n";
return;
}
Node*ptr = head;
Node*prev;
while(ptr!=NULL){
prev = ptr;
ptr=ptr->next;
delete prev;
}
head = NULL;
cout<<"\n\nLIST DELETED SUCCESSFULLY !\n\n";
}
//swap_nodes_without_swapping_values function
void llist::swap_nodes_without_swapping_values(int val1,int val2){
Node* ptr = head;
Node* prev,*curr1,*curr1prev,*curr2,*curr2prev;
int counter =0;
while(ptr!=NULL){
counter++;
ptr=ptr->next;
}
if(head==NULL){
cout<<"\n\nEMPTY LIST !\n\n";
return;
}
int val1c = searchele(val1);
int val2c = searchele(val2);
if(val1c==0||val2c==0){
cout<<"\n\nONE OF THE TWO ELEMENTS NOT IN THE LIST, LIST REMAINS UNCHANGED !\n\n";
return;
}
ptr=head;
prev = NULL;
while(ptr!=NULL){
if(ptr->data==val1){
curr1 = ptr;
curr1prev = prev;
}else if(ptr->data==val2){
curr2 = ptr;
curr2prev =prev;
}
prev = ptr;
ptr = ptr->next;
}
ptr=head;
if( (ptr->data==val1||ptr->data==val2)&&abs(val1c-val2c)==1 ){
head=curr2;
curr1->next = curr2->next;
curr2->next = curr1;

cout<<"\n\nMODIFICATIONS SUCCESSFUL !\n\n";
}else if((ptr->data==val1||ptr->data==val2)){
head = curr2;
curr2prev->next=curr2->next;
curr2->next= curr1->next;
curr1->next=curr2prev->next;
curr2prev->next=curr1;

cout<<"\n\nMODIFICATIONS SUCCESSFUL !\n\n";
}else if(abs(val1c-val2c)==1){
//for adjacent nodes !
ptr =head;
prev = head;
for(int i=1;i<=counter;i++){
if(i==val1c||i==val2c){
curr1prev->next=curr2;
curr2prev->next=curr2->next;
curr2->next = curr1;

cout<<"\n\nMODIFICATIONS SUCCESSFUL !\n\n";
break;
}
prev=ptr;
ptr=ptr->next;
}
}else{
//for non adjacent nodes !
ptr =head;
prev = head;
for(int i=1;i<=counter;i++){
if(i==val1c||i==val2c){
curr1prev->next=curr2;
curr2prev->next=curr2->next;
curr2->next=curr1->next;
curr1->next=curr2prev->next;
curr2prev->next=curr1;

cout<<"\n\nMODIFICATIONS SUCCESSFUL !\n\n";
break;
}
prev=ptr;
ptr=ptr->next;
}
}
}

//HOPE YOU LIKED IT :)