import java.util.*;
/* Class Node */
class Node
{
protected int
data;
protected Node
link;
/* Constructor
*/
public Node()
{
link = null;
data = 0;
}
/* Constructor
*/
public Node(int
d,Node n)
{
data = d;
link = n;
}
/* Function to set link to next Node */
public void
setLink(Node n)
{
link = n;
}
/* Function to set data to current Node */
public void
setData(int d)
{
data = d;
}
/* Function to get link to next node */
public Node
getLink()
{
return link;
}
/* Function to get data from current Node */
public int
getData()
{
return data;
}
}
/* Class
linkedStack */
class linkedStack
{
protected Node top
;
protected int size
;
/* Constructor
*/
public
linkedStack()
{
top = null;
size = 0;
}
/* Function to check if stack is empty */
public boolean
isEmpty()
{
return top ==
null;
}
/* Function to get the size of the stack */
public int
getSize()
{
return size;
}
/* Function to push an element to the stack */
public void
push(int data)
{
Node nptr =
new Node (data, null);
if (top ==
null)
top =
nptr;
else
{
nptr.setLink(top);
top =
nptr;
}
size++ ;
}
/* Function to pop an element from the stack */
public int pop()
{
if (isEmpty()
)
throw new
NoSuchElementException("Underflow Exception") ;
Node ptr =
top;
top =
ptr.getLink();
size-- ;
return
ptr.getData();
}
/* Function to check the top element of the
stack */
public int peek()
{
if (isEmpty()
)
throw new
NoSuchElementException("Underflow Exception") ;
return
top.getData();
}
/* Function to display the status of the stack
*/
public void
display()
{
System.out.print("\nStack = ");
if (size == 0)
{
System.out.print("Empty\n");
return ;
}
Node ptr =
top;
while (ptr !=
null)
{
System.out.print(ptr.getData()+" ");
ptr =
ptr.getLink();
}
System.out.println();
}
}
/* Class LinkedStackImplement */
public class LinkedStackImplement
{
public static void
main(String[] args)
{
Scanner scan =
new Scanner(System.in);
/* Creating
object of class linkedStack */
linkedStack ls
= new linkedStack();
/* Perform
Stack Operations */
System.out.println("Linked Stack Test\n");
char ch;
do
{
System.out.println("\nLinked Stack Operations");
System.out.println("1. push");
System.out.println("2. pop");
System.out.println("3.
peek");
System.out.println("4. check empty");
System.out.println("5. size");
int choice
= scan.nextInt();
switch
(choice)
{
case 1 :
System.out.println("Enter
integer element to push");
ls.push( scan.nextInt() );
break;
case 2 :
try
{
System.out.println("Popped Element = "+ ls.pop());
}
catch
(Exception e)
{
System.out.println("Error : " + e.getMessage());
}
break;
case 3 :
try
{
System.out.println("Peek Element = "+ ls.peek());
}
catch
(Exception e)
{
System.out.println("Error : " + e.getMessage());
}
break;
case 4 :
System.out.println("Empty status = "+ ls.isEmpty());
break;
case 5 :
System.out.println("Size = "+ ls.getSize());
break;
case 6 :
System.out.println("Stack = ");
ls.display();
break;
default :
System.out.println("Wrong Entry \n ");
break;
}
/* display
stack */
ls.display();
System.out.println("\nDo you want to continue (Type y or n)
\n");
ch =
scan.next().charAt(0);
} while (ch ==
'Y'|| ch == 'y');
}
}
