Singly link list

#include<bits/stdc++.h>
using namespace std;

class Node{
public:
    int data;
    Node *next;
};
class Linklist{
public:
    Node *head;
public:
    Linklist(){
        head = NULL;
    }
    void insert_at_first(int  x){
        Node *newNode = new Node();
        newNode->data = x;
        newNode->next = head;
        head = newNode;
    }
    void insertValue(int index,int  x){
        Node *temp = head;
        if( index < 0 && temp == NULL)
        {
            cout<<"Insert Can not possible";
        }
        int cont=0;
        while(index > cont && temp)
        {
            temp = temp->next;
            cont++;
        }

        Node *newNode = new Node();
        newNode->data = x;
        newNode->next = temp->next;
        temp->next = newNode;
    }
    void deleteValue( int key){
        Node *temp = head , *prev;
        if( temp != NULL && temp->data == key)
        {
            head = temp->next;
            delete(temp);
            return;
        }
        while( temp != NULL && temp->data != key)
        {
            prev = temp;
            temp = temp->next;
        }
        if(temp == NULL)
        {
            cout<<"Value is not found"<<endl;
            return;
        }
        prev->next = temp->next;
        delete(temp);
    }
    void display(){
        Node *temp = head;
        if(temp == NULL)
        {
            cout<<"Link List is Empty"<<endl;
            return;
        }
        while(temp != NULL)
        {
            cout<<temp->data<<" ";
            temp = temp->next;
        }
        cout<<endl;
    }
};
int main()
{
    Linklist ll;
    cout<<"how many value you want to insert: ";
    int n;
    cin>>n;
    int value;
    cin>>value;
    ll.insert_at_first(value);

    for(int i=0;i<n-1;i++)
    {
        cin>>value;
        ll.insertValue(i,value);
    }
    ll.display();
    cout<<endl<<"which value you want to delete ";
    cin>>value;
    ll.deleteValue(value);
    ll.display();

}