undoLinked

#include<iostream>
#include<string.h>
#include<stdlib.h>
using namespace std;
class NODE
{
public:
	char *data;
	NODE *next;
public:
	NODE(char *val="\0",NODE *link=NULL)
	{
		data=new char[20];
		strcpy(data,val);
		next=link;
	}
	NODE *init()
	{
		return NULL;
	}
	NODE *insertTail(char *val)
	{	
		NODE *temp=this;
		if(!temp) return new NODE(val,NULL);
		while(temp->next)
		{
			temp=temp->next;
		}
		temp->next=new NODE(val,NULL);
		return this;
	}
	bool del()
	{
		NODE *temp=this;
		if(!this) return 0;
		while((temp->next)->next!=NULL)
		{
			temp=temp->next;
		}
		temp->next=NULL;
		return 1;
	}
	void printList()
	{
		//cout<<this->data<<'\n';
		NODE *temp=this->next;
		while(temp)
		{
			cout<<' '<<temp->data;
			temp=temp->next;
		}
	}
};
class STACK:public NODE
{
	NODE *top;
public:
	STACK()
	{
		top=new NODE;
	}
	bool push(char *val)
	{
		NODE *t=new NODE(val,top);
		if(t==NULL) 
			return 0;
		top=t;
		return 1;
	}
	bool pop()
	{
		if(isEmpty())
			return 0;
		top=top->next;
	}
	char *Top()
	{
		return top->data;
	}
	bool isEmpty()
	{
		if(top->next==NULL)
			return 1;
		else
			return 0;
	}
};
int main()
{
	system("clear");cout<<' ';
	STACK s,sk;int i=0,n=0,m=0;
	NODE *a;
	a=new NODE;
	char *str; 
	str=new char[20];
	cin>>str;
	char *ch; 
	ch=new char[20];
	char *ch1; 
	ch1=new char[20];
	while(strcmp(str,"#")!=0)
	{
		if((strcmp(str,"z")==0)&&(!s.isEmpty()))
		{
			if((i==0)||(m>=n))
			{
				s.pop();
				a->del();
				system("clear");
				a->printList();
				cin>>str;
			}
			else
			{
				ch=s.Top();
				ch1=sk.Top();
				if(ch[0]==ch1[0])
				{
					s.pop();		
					a->del();
				}
				ch=sk.Top();sk.pop();
				s.push(ch);
				a->insertTail(ch);
				system("clear");
				a->printList();m++;
				cin>>str;
			}	
		}
		else if((strcmp(str,"b")==0)&&(!s.isEmpty()))
		{
			ch=s.Top();s.pop();
			sk.push(ch);
			ch[strlen(ch)-1]='\0';
			a->del();
			if(strcmp(ch,"\0")!=0)
			{
				s.push(ch);
				a->insertTail(ch);
			}
			system("clear");
			a->printList();
			i=1;n++;m=0;
			cin>>str;
		}
		else
		{
			if((strcmp(str,"b")!=0)&&(strcmp(str,"z")!=0))
			{
				s.push(str);i=0;n=0;
				a->insertTail(str);
				cin>>str;
			}
			else
			{
				system("clear");
				cin>>str;
			}
		}
	}
	return 1;
}