Exercise_2.java

public class StackAsLinkedList { 
 
 StackNode root; 
 
 static class StackNode { 
 int data; 
 StackNode next; 
 
 StackNode(int data) 
 { 
 //Constructor here 
 } 
 } 
 
	
 public boolean isEmpty() 
 { 
 //Write your code here for the condition if stack is empty. 
 } 
 
 public void push(int data) 
 { 
 //Write code to push data to the stack. 
 } 
 
 public int pop() 
 { 	
	//If Stack Empty Return 0 and print "Stack Underflow"
 //Write code to pop the topmost element of stack.
	//Also return the popped element 
 } 
 
 public int peek() 
 { 
 //Write code to just return the topmost element without removing it.
 } 
 
	//Driver code
 public static void main(String[] args) 
 { 
 
 StackAsLinkedList sll = new StackAsLinkedList(); 
 
 sll.push(10); 
 sll.push(20); 
 sll.push(30); 
 
 System.out.println(sll.pop() + " popped from stack"); 
 
 System.out.println("Top element is " + sll.peek()); 
 } 
}