LinkedHashSet Class
This is a subclass of HashSet class and does not contain any additional members on its own.It is a generic class that has declaration:
class LinkedHashSet<T>
Here.T represents generic type parameter.
LinkedHashSet internally uses a linked list to store the elements.
Stack Class
A stack represents a group of elements stored in LIFO.This means that the element which is stored as a last element into the stack will be the first element to be removed from the stack.
There are three operation can be performed on stack:
Push() ----Inserting an element in stack.
Pop()------Deleting an element from stack.
Peek()-----Searching an element from stack.
Stack Class Methods
boolean empty();
element peek();
element pop();
element push(element obj);
int search(Object obj);
What is Auto Boxing?
Ans: Converting a primitive data type into an object form automatically is called Auto-Boxing.Auto Boxing is done in generic types.
Program:
/**
*
*/
package com.collectionpack;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Stack;
/**
* @author Abhinaw.Tripathi
*
*/
public class StackApp
{
/**
* @param args
* @throws IOException
* @throws NumberFormatException
*/
public static void main(String[] args) throws NumberFormatException, IOException
{
Stack<Integer> st=new Stack<>();
int choice = 0;
int position,element;
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
while(choice < 4)
{
System.out.println("Stack Operation");
System.out.println("1 Push an element");
System.out.println("2 Pop an element");
System.out.println("3 Search an element?");
System.out.println("4 Exist");
choice=Integer.parseInt(br.readLine());
switch (choice)
{
case 1:
System.out.println("Enter element: ");
element=Integer.parseInt(br.readLine());
st.push(element);
break;
case 2:
Integer obj=st.pop();
System.out.println("Popped= "+ obj);
break;
case 3:
System.out.println("Which element?");
element=Integer.parseInt(br.readLine());
position=st.search(element);
if(position == -1)
System.out.println("Element not found");
else
System.out.println("Position:" +position);
break;
default:
return;
}
System.out.println("stack contents: "+st);
}
}
}
Output:
Stack Operation
1 Push an element
2 Pop an element
3 Search an element?
4 Exist
1
Enter element:
52
stack contents: [52]
Stack Operation
1 Push an element
2 Pop an element
3 Search an element?
4 Exist