Stack

Program

#include<iostream>

using namespace std;

struct node

{

int data;

node *next;

};

class ListStack{

node *head;

public:

ListStack()

{

head=NULL;

}

void push(int info)

{

node *NewNode=new node;

NewNode->data=info;

NewNode->next=head;

head=NewNode;

}

int pop()

{

if(IsEmpty())

{

cout<<"Underflow occurs ";

return NULL;

}

int info;

node *cur=head;

info=head->data;

head=head->next;

delete cur;

            return info;

}

int IsEmpty()

{

if(head==NULL)

return 1;

return 0;

}

};

int main()

{

ListStack s;

s.push(20);

cout<<s.pop();

cout<<s.pop();

}