#include <stdio.h>
#include <stdlib.h>

struct node
{
    int data;
    struct node*next;
};
struct node*head=NULL;

void push(int val)
{
    struct node*new=malloc(sizeof(struct node));
    new->data=val;
    new->next=head;
    head=new;
    printf("The element %d has been pushed into the stack successfully!\n", val);
}

void pop()
{
    struct node*temp;
    if(head==NULL)
    printf("The Stack is empty!\n");
    else
    {
        printf("The element %d has been popped out of the stack successfully!\n", head->data);
        temp=head;
        head=head->next;
        free(temp);
    }
}

void print()
{
    struct node*temp=head;
    printf("The elements of the stack are :\n");
    while(temp!=NULL)
    {
        printf("%d ", temp->data);
        temp=temp->next;
    }
}

void main()
{
  int a,n;
  
  do
   {
    printf("Enter 1 for push, 2 for pop, 3 for display and 4 to exit the program\n");
  scanf("%d", &a);
    switch(a)
    {
        case 1 :printf("Enter the element to be pushed\n");
                scanf("%d", &n);
                push(n);
                break;
        case 2 : pop();
                break;
        case 3 : print();
                break;
        case 4 : printf("The program has been terminated\n");
                break;
        case 5 : printf("Enter a valid number!\n");
                break;
    }
   }
   while(a!=4);
    
}