oops/32_linked-list.cpp at main · kumari06khushi/oops · GitHub

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#include<iostream>
using namespace std;

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

Node(int val){
    data=val;
    next=NULL;
}
};
class List{
    Node* head;
    Node*tail;

public:
    List(){
head = tail = NULL;
}


void push_front(int val){
    Node*newNode=new Node(val);
    if(head == NULL){
        head = tail = newNode;
        return;
    }
else{
   newNode->next = head;
   head = newNode;
}
}


void push_back(int val){
    Node*newNode=new Node(val);
    if(head == NULL){
        head = tail = newNode;
        return;
    }

else{
   tail->next = newNode;
   tail = newNode;
}
}


void pop_front(){
  if(head == NULL){
    cout<<"ll is empty\n";
    return ;
  }
  Node* temp = head;
  head = head->next; //connection
  temp->next = NULL;
  delete temp;

}


void pop_back(){
  if(head == NULL){
    cout<<"ll is empty\n";
    return ;
  }
  Node* temp = head;
  while(temp->next != tail){
    temp = temp->next;
  }
  temp->next = NULL;
  delete tail;
  tail = temp;
}


void insert(int val,int pos){
    if(pos<0){
        cout<<"invalid pos\n";
        return;
    }
    if(pos == 0){
        push_front(val);
        return;
    }
    Node* temp = head;
    for(int i=0; i<pos-1; i++){
        temp = temp->next;
    }
    Node* newNode = new Node(val);
    newNode->next = temp->next;
    temp->next = newNode;
}

int search(int key){
    Node* temp = head;
    int idx = 0;
    while(temp != NULL){
        if(temp->data == key){
            return idx;
        }
        temp = temp->next;
        idx++;
    }
   return -1;
}

void printLL(){
    Node* temp=head;
    while(temp !=NULL){
  cout<<temp->data<<"-->"<<" ";

  temp=temp->next;
    }
    cout<<endl;
}

};
int main(){
List ll;
ll.push_front(1);
ll.push_front(2);
ll.push_front(3);
ll.printLL();

ll.push_back(4);
ll.printLL();

ll.pop_front();
ll.printLL();

ll.pop_back();
ll.printLL();

ll.insert(6,1);
ll.printLL();

cout<< ll.search(2)<<endl;

    return 0;
}