C++ OOP LinkedList Implementation

#include <iostream>
using namespace std;
class Linklist{
public:
	class Node{
	int data;
	Node*next;
	public:
		Node(){}
		Node(Node*next,int data){
		this->data=data;
		this->next=next;
		}
		friend class Linklist;
	};
private:
	Node*head,*tail;
public:
	Linklist(){
	head=tail=nullptr;
	}
	void insertonhead(int val){
	if(head==nullptr)
		{
	Node*temp=new Node;
	temp->data=val;
	temp->next=NULL;
	head=temp;
	tail=temp;
	}
	else {
	Node*temp=new Node;
    temp->data=val;
	temp->next=head;
	head=temp;
	}
	}
	void Deletefromhead(){
	head=head->next;
	}
	void Deletefromtail(){
	Node*prev=head,*curr=head;
	while(curr->next!=nullptr){
	prev=curr;
	curr=curr->next;
	}
	prev->next=nullptr;
	tail=prev;
	}
	void insertatail(int value)
{
	Node* node = new Node;
	node->data=value;
	if (head == nullptr)
	{
	node->next=nullptr;
	head=node;
	tail=node;
	}
	else {
		node->next=nullptr;
		tail->next=node;
		tail=node;
	}

}
int getsize(){
int count=0;
Node*temp=head;
while(temp!=nullptr){
count++;
temp=temp->next;
}
return count;
}
void getMiddle()
{
  Node *current=head;
  int middle = getsize();
  //cout<<middle;
  middle=middle/2;
  int x=0;
  while(x!=middle)
  {
     current=current->next;
 x++;
  }
  cout<< current->data<<endl;
}
bool isempty(){
	if(head==nullptr){
	return true;
	}
	else
		return false;
}
void disp(){
		Node*temp=head;
	if(head!=nullptr){
		while(temp!=nullptr)
	{
		cout<<"->"<<temp->data;
	    temp=temp->next;
	}
	}
}
int getAverage(){






}
void insertAfter(int val,int key){
Node *current = head;
while(current->data!=key){
current=current->next;
}

Node *n = new Node;
n->data=val;
n->next=current->next;
current=n;

}
int getMax(){
Node *current = head;
int max=0;
int s=getsize();
while(current!=nullptr){

if(max<current->data){
max=current->data;
}

current=current->next;
}
return max;
}
int getMin(){
Node *current = head;
int min=0;
int s=getsize();
while(current!=nullptr){

if(min>current->data){
min=current->data;
}

current=current->next;
}
return min;
}
};
int main(){
	Linklist l1;
	l1.insertonhead(8);
	l1.insertonhead(16);
	l1.insertonhead(48);
	l1.insertonhead(87);
	l1.insertonhead(54);
	l1.insertonhead(21);
	l1.disp();
	cout<<endl;
	cout<<l1.getsize()<<endl;
	cout<<endl;
	l1.insertatail(41);
	l1.disp();
	l1.Deletefromhead();
	cout<<endl;
	l1.disp();
		cout<<endl;
			l1.Deletefromtail();
	l1.disp();
	cout<<endl;
	l1.getMiddle();
	cout<<endl;
	cout<<l1.getMax();
	cout<<endl;
	cout<<l1.getMin();
			system("pause");
	return 0;
}