addNodeAtPosition.c++

#include<iostream>
using namespace std;

class Node{
    public:
    int val;
    Node* next;
    Node(int data){
        val = data;
        next = NULL;
    }
};

void insertAtHead(Node* &head, int val){
    Node* new_node = new Node(val);

    new_node -> next = head;
    head = new_node;
}

void insertAtTail(Node* &head, int val){
    Node* new_node = new Node(val);
    Node* temp = head;

    while(temp->next != NULL){
        temp = temp->next;
    }
    temp->next = new_node;
}

void insertAtPosition(Node* &head, int val, int pos){
    if(pos == 0){
        insertAtHead(head, val);
        return;
    }
    Node* new_node = new Node(val);
    Node* temp = head;

    int curr_pos = 0;
    while(curr_pos != pos-1){
        temp = temp->next;
        curr_pos++;
    }
    new_node->next = temp->next;
    temp->next = new_node;
}
void display(Node* head){
    Node* temp = head;

    while(temp!= NULL){
        cout<<temp->val<<"->";
        temp = temp->next;
    }
    cout<<"NULL"<<endl;
}

int main(){

    Node* head = NULL;

    insertAtHead(head,2);
    display(head);
    insertAtHead(head,1);
    display(head);
    insertAtTail(head,3);
    display(head);
    insertAtPosition(head,4,1);
    display(head);
    return 0;

}