stack linked list

#include <iostream>
using namespace std;

struct stack{

    int data;
    struct stack *next;

    };
typedef struct stack stack;
    stack *head;
void push(int x){

    stack *temp2;

    if(head == NULL){
        head = new stack();
        head->data = x;
        head->next = NULL;

        }
    else{

        temp2 = new stack();
        temp2->data=x;
        temp2->next = head;
        head = temp2;

        }


    }

int top(){

    if(head == NULL){
        cout<<"empty";
    return -1;
}
    return head->data;

    }

void pop(){

    stack *temp = head;
    if(head == NULL){
        cout<<"emtpy\n";
        return;
    }
    if(head->next == NULL){
        head = NULL;
        delete head;
    }
    else{

         head = head->next;
         delete temp;

        }


    }



void display(){
    stack *temp = head;
    while(temp !=NULL){
        printf("%d ", temp->data);
        temp = temp->next;

        }
    cout<<endl;
    }

int main(int argc, char **argv)
{
    head = NULL;
    push(10);
    push(20);
    push(30);
    push(40);
    display();
    pop();
    display();
    return 0;
}