STACK IMPLEMENTATION USING LINKLIST

// stack_implemention_using_linked_list.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <stdlib.h>
#include <iostream>
using namespace std ;

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

struct stack *top = NULL;
struct stack *ptop= NULL;
struct stack *last= NULL;

class stack_List
{
protected :
struct stack * node;
stack_List *stack_obj;
/*stack_List()
{
node = NULL;
}*/

/*~stack_List()
{
delete stack_obj;
}*/

public :
void push(int data);
void pop ();
void printData();

};

void stack_List::push(int data)
{
struct stack *temp  = NULL;
temp = new (nothrow) stack ; // notthorw if memroy not availble in heap area then it won't throe badallocation insated of it will return null

if(temp == NULL)
{
cout << "Memory Allocation Fialed";
}

if(top == NULL )
{

temp->data = data;
temp->next = NULL;
top = temp;
ptop = temp;
last = temp;
}

else{
temp->data = data;
top->next  =  temp ;
temp->next = NULL;
ptop = top;
top = temp;;
}
}

void stack_List::pop(){
struct stack * temp =  NULL;

if(top == NULL)
{
cout << "stack underflow" ;
return;
}
temp = last;
while(temp->next != top)
{
temp = temp->next;
}
top= temp;
temp = temp->next;
top->next =  NULL;
//ptop = top ;

delete temp;
}

void stack_List::printData(){
struct stack * temp =  NULL;
temp = last;

while(temp)
{
cout << temp->data <<endl;
temp = temp->next;
}
}

int _tmain(int argc, _TCHAR* argv[])
{
stack_List *stack_obj = new stack_List();

cout << "                      ***********************************                     " << endl;
cout << "                      STACK IMPLEMENTATION USING LINKLIST                     " << endl;
cout << "                      ***********************************                     " << endl;

cout <<endl;
cout <<endl;

stack_obj ->push(10);
stack_obj ->push(20);
stack_obj ->push(50);

cout << " printing stack data" << endl;
cout <<endl;
stack_obj ->printData();

stack_obj->pop();
cout <<endl;


cout << " printing stack data after 1st pop element"<<endl;
cout <<endl;
stack_obj ->printData();
delete stack_obj;

cout <<endl;

system("pause");
return 0;
}