Code:
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 linkedQueue */
class linkedQueue
{
protected Node front, rear;
public int size;
/* Constructor */
public linkedQueue()
{
front = null;
rear = null;
size = 0;
}
/* Function to check if queue is empty */
public boolean isEmpty()
{
return front == null;
}
/* Function to get the size of the queue */
public int getSize()
{
return size;
}
/* Function to insert an element to the queue */
public void insert(int data)
{
Node nptr = new Node(data, null);
if (rear == null)
{
front = nptr;
rear = nptr;
}
else
{
rear.setLink(nptr);
rear = rear.getLink();
}
size++ ;
}
/* Function to remove front element from the queue */
public int remove()
{
if (isEmpty() )
throw new NoSuchElementException("Underflow Exception");
Node ptr = front;
front = ptr.getLink();
if (front == null)
rear = null;
size-- ;
return ptr.getData();
}
/* Function to check the front element of the queue */
public int peek()
{
if (isEmpty() )
throw new NoSuchElementException("Underflow Exception");
return front.getData();
}
/* Function to display the status of the queue */
public void display()
{
System.out.print("\nQueue = ");
if (size == 0)
{
System.out.print("Empty\n");
return ;
}
Node ptr = front;
while (ptr != rear.getLink() )
{
System.out.print(ptr.getData()+" ");
ptr = ptr.getLink();
}
System.out.println();
}
}
/* Class LinkedQueueImplement */
public class LinkedQueueImplement
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
/* Creating object of class linkedQueue */
linkedQueue lq = new linkedQueue();
/* Perform Queue Operations */
System.out.println("Linked Queue Test\n");
char ch;
do
{
System.out.println("\nQueue Operations");
System.out.println("1. insert");
System.out.println("2. remove");
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 insert");
lq.insert( scan.nextInt() );
break;
case 2 :
try
{
System.out.println("Removed Element = "+ lq.remove());
}
catch (Exception e)
{
System.out.println("Error : " + e.getMessage());
}
break;
case 3 :
try
{
System.out.println("Peek Element = "+ lq.peek());
}
catch (Exception e)
{
System.out.println("Error : " + e.getMessage());
}
break;
case 4 :
System.out.println("Empty status = "+ lq.isEmpty());
break;
case 5 :
System.out.println("Size = "+ lq.getSize());
break;
default :
System.out.println("Wrong Entry \n ");
break;
}
/* display queue */
lq.display();
System.out.println("\nDo you want to continue (Type y or n) \n");
ch = scan.next().charAt(0);
} while (ch == 'Y'|| ch == 'y');
}
}
Output:
Linked Queue Test
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
4
Empty status = true
Queue = Empty
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
1
Enter integer element to insert
24
Queue = 24
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
1
Enter integer element to insert
5
Queue = 24 5
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
1
Enter integer element to insert
9
Queue = 24 5 9
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
1
Enter integer element to insert
72
Queue = 24 5 9 72
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
1
Enter integer element to insert
14
Queue = 24 5 9 72 14
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
1
Enter integer element to insert
1
Queue = 24 5 9 72 14 1
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
5
Size = 6
Queue = 24 5 9 72 14 1
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
3
Peek Element = 24
Queue = 24 5 9 72 14 1
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
2
Removed Element = 24
Queue = 5 9 72 14 1
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
2
Removed Element = 5
Queue = 9 72 14 1
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
2
Removed Element = 9
Queue = 72 14 1
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
5
Size = 3
Queue = 72 14 1
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
3
Peek Element = 72
Queue = 72 14 1
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
2
Removed Element = 72
Queue = 14 1
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
2
Removed Element = 14
Queue = 1
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
3
Peek Element = 1
Queue = 1
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
2
Removed Element = 1
Queue = Empty
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
2
Error : Underflow Exception
Queue = Empty
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. size
4
Empty status = true
Queue = Empty
Do you want to continue (Type y or n)
n
More Java Programs:
