doublystack.cpp

#include<iostream>
#include<cstdio>
void push(int x);
void pop();
void search(int x);
using namespace std;
typedef struct alvi
{
    int data;
    struct alvi *prev;
    struct alvi *next;
}node;
node *head=NULL;
node *tail=NULL;
int main(void)
{

    push(1);
    push(2);
    push(3);
    search(10);
    //search(4);
    pop();
    return 0;
}
void push(int x)
{
    node *newNode = new node();
    newNode->data = x;
    if(head==NULL)
    {
        cout<<"First node pushed"<<endl;
        newNode->prev=NULL;
        newNode->next=NULL;
        head=newNode;
        tail=newNode;

    }
    else
    {
        cout<<"other node pushed"<<endl;
        head->prev=newNode;
        newNode->next=head;
        head=newNode;

        //head= newNode;
    }
}
void pop()
{
    node *cursor;
    cursor = tail;
    while(cursor!=NULL)
    {
        cout<<cursor->data;
        cursor=cursor->prev;
    }
    cout<<endl;
    //cout<<cursor->prev->data;
}

void search(int x)
{
    node *cursor1;
    cursor1 = head;
    int flag=0;
    int counter = 1;
    while(cursor1!=NULL)
    {
        if(cursor1->data==x)
        {
            flag=1;
            cout<<"found"<<endl;;
            cout<<"element number : "<<counter<<endl;
            break;
        }
        cursor1=cursor1->next;
        counter++;
    }
    if(flag==0)
    {
        cout<<"not found"<<endl;
    }
}