#include <iostream>

using namespace std;

struct Node
{
    int Data;
    Node *next;
} *top;

void popStack()
{
    Node *temp, *var=top;
    if(var==top)
    {
        top = top->next;
        delete var;
    }
    else
    cout << endl << "Stack is Empty" << endl;
}

void push(int value)
{
    Node *temp = new Node;
    temp->Data=value;
    if (top == NULL)
    {
         top=temp;
         top->next=NULL;
    }
    else
    {
        temp->next=top;
        top=temp;
    }
}

void display()
{
     Node *var=top;
     if(var!=NULL)
     { 
          cout << endl << "Elements are:" << endl;
          while(var!=NULL)
          {
               cout << var->Data << " ";
               var=var->next;
          } 
     cout << endl;
     }
     else
     cout << endl << "Stack is Empty";
}

int main(int argc, char *argv[])
{
     int i=0;
     top=NULL;
     
     cout << endl <<" 1. Push to stack";
     cout << endl <<" 2. Pop from Stack";
     cout << endl <<" 3. Display data of Stack";
     cout << endl <<" 4. Exit" << endl;
     
     while(1)
     {
          cout << endl << " Choose Option: ";
          cin >> i;
          
          switch(i)
          {
               case 1:
               {
               int value;
               cout << "Enter a value to push into Stack: ";
               cin >> value;
               push(value);
               display();
               break;
               }
               case 2:
               {
               popStack();
               display();
               break;
               }
               case 3:
               {
               display();
               break;
               }
               case 4:
               {
               Node *temp;
               while(top!=NULL)
               {
                    temp = top->next;
                    delete top;
                    top=temp;
               }
               exit(0);
               } 
               default:
               {
               cout << endl << "Wrong choice..." << endl;
               }
         }
    }
}