Super Market Stack with Queue using LinkedList

main.cpp

#include <iostream>
using namespace std;

/*
Inside a supermarket, there was a queue of customers at the cashier (4 customers), 
named "1,2,3, and 4" The first customer paid for her products and then left the market, 
after that a VIP customer named "5" entered the shop and he will pay for his products before customers "2,3, and 4".

Implement this scenario using Stack with Queue using LinkedList , and then print the final queue.
*/

struct node{
  int data;
  node *next;
};

node *head = NULL;

void enqueue(int value){
    node* new_node = new node;
    new_node-> data = value;
    new_node -> next = NULL;
    if(head == NULL)
        head = new_node;
    else{
        node * temp = head;
        while(temp->next != NULL)
            temp = temp -> next;
        temp -> next = new_node;
    }
}

void dequeue(){
    node *first_node = head;
    head = first_node->next;
    delete(first_node);
}

void push(int value){
    node* new_node = new node;
    new_node -> data = value;
    if(head == NULL){
        new_node -> next = NULL;
        head = new_node;
    }
    else{
        new_node->next = head;
        head = new_node;
    }
}

void display(){
    node * temp = head;
    while(temp != NULL){
        cout<<'\t'<<temp->data<<endl;
        temp = temp->next;
    }
}

int main() {
   enqueue(1); //Insert Last
   enqueue(2); //Insert Last
   enqueue(3); //Insert Last
   enqueue(4); //Insert Last
   display();  //Print All elements
   cout<<endl;
   dequeue();  //Delete First
   display();  //Print All elements
   cout<<endl;
   push(5);    //Insert First
   display();  //Print All elements
   cout<<endl;
   return 0;
}