insert_at_index_in_LL.cpp

#include<bits/stdc++.h>
using namespace std;
class Node{
    public:
    int data;
    Node* next;

};
Node* head;


void Create(int Arr[],int size){
    Node* temp;
    Node* last;

    head = new Node;
    head->data= Arr[0];
    head->next= nullptr;
    
    last=head;
    
    // creating linked list

    for(int i=1;i<size;i++ ){
        temp = new Node;

        temp->data=Arr[i];
        temp->next=nullptr;

        last->next=temp;
        last=temp;

    }
    
}

// insert at a given index

void Insert_at_index(Node* P,int key,int pos){
   if (pos < 0) {
        cout << "Invalid position\n";
        return;
    }

    Node* q = new Node;
    q->data = key;
    
    if(pos == 0){
        q->next = head;
        head = q;
    }
    else{
        for (int i = 0; i < pos - 1 && P; i++) {
            P = P->next;
        }
        if (!P) {
            cout << "Invalid position\n";
            return;
        }
        q->next = P->next;
        P->next = q;
    } 
}
void Display(Node* P){
    while (P!=nullptr)
    {
        cout<<P->data<<"->";
        P=P->next;
        
    }
}

int main(){

    int A[]={1,2,3,4,5,6};
    int size=(sizeof(A)/sizeof(A[0]));
    
    Create(A,size);
    Insert_at_index(head,7,6);
    Insert_at_index(head,8,7);
    Insert_at_index(head,9,8);
    Insert_at_index(head,76,76);

    Display(head);

    return 0;
        


}