Code:
import java.util.*;
/* Class arrayQueue */
class arrayQueue
{
protected int Queue[] ;
protected int front, rear, size, len;
/* Constructor */
public arrayQueue(int n)
{
size = n;
len = 0;
Queue = new int[size];
front = -1;
rear = -1;
}
/* Function to check if queue is empty */
public boolean isEmpty()
{
return front == -1;
}
/* Function to check if queue is full */
public boolean isFull()
{
return front==0 && rear == size -1 ;
}
/* Function to get the size of the queue */
public int getSize()
{
return len ;
}
/* Function to check the front element of the queue */
public int peek()
{
if (isEmpty())
throw new NoSuchElementException("Underflow Exception");
return Queue[front];
}
/* Function to insert an element to the queue */
public void insert(int i)
{
if (rear == -1)
{
front = 0;
rear = 0;
Queue[rear] = i;
}
else if (rear + 1 >= size)
throw new IndexOutOfBoundsException("Overflow Exception");
else if ( rear + 1 < size)
Queue[++rear] = i;
len++ ;
}
/* Function to remove front element from the queue */
public int remove()
{
if (isEmpty())
throw new NoSuchElementException("Underflow Exception");
else
{
len-- ;
int ele = Queue[front];
if ( front == rear)
{
front = -1;
rear = -1;
}
else
front++;
return ele;
}
}
/* Function to display the status of the queue */
public void display()
{
System.out.print("\nQueue = ");
if (len == 0)
{
System.out.print("Empty\n");
return ;
}
for (int i = front; i <= rear; i++)
System.out.print(Queue[i]+" ");
System.out.println();
}
}
/* Class QueueImplement */
public class QueueImplement
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
System.out.println("Array Queue Test\n");
System.out.println("Enter Size of Integer Queue ");
int n = scan.nextInt();
/* creating object of class arrayQueue */
arrayQueue q = new arrayQueue(n);
/* Perform Queue Operations */
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. check full");
System.out.println("6. size");
int choice = scan.nextInt();
switch (choice)
{
case 1 :
System.out.println("Enter integer element to insert");
try
{
q.insert( scan.nextInt() );
}
catch(Exception e)
{
System.out.println("Error : " +e.getMessage());
}
break;
case 2 :
try
{
System.out.println("Removed Element = "+q.remove());
}
catch(Exception e)
{
System.out.println("Error : " +e.getMessage());
}
break;
case 3 :
try
{
System.out.println("Peek Element = "+q.peek());
}
catch(Exception e)
{
System.out.println("Error : "+e.getMessage());
}
break;
case 4 :
System.out.println("Empty status = "+q.isEmpty());
break;
case 5 :
System.out.println("Full status = "+q.isFull());
break;
case 6 :
System.out.println("Size = "+ q.getSize());
break;
default : System.out.println("Wrong Entry \n ");
break;
}
/* display Queue */
q.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:
Array Queue Test
Enter Size of Integer Queue
5
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. 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. check full
6. 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. check full
6. size
1
Enter integer element to insert
6
Queue = 24 6
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
1
Enter integer element to insert
16
Queue = 24 6 16
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
1
Enter integer element to insert
19
Queue = 24 6 16 19
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
1
Enter integer element to insert
32
Queue = 24 6 16 19 32
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
1
Enter integer element to insert
14
Error : Overflow Exception
Queue = 24 6 16 19 32
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
5
Full status = true
Queue = 24 6 16 19 32
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
3
Peek Element = 24
Queue = 24 6 16 19 32
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
2
Removed Element = 24
Queue = 6 16 19 32
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
2
Removed Element = 6
Queue = 16 19 32
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
6
Size = 3
Queue = 16 19 32
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
3
Peek Element = 16
Queue = 16 19 32
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
2
Removed Element = 16
Queue = 19 32
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
2
Removed Element = 19
Queue = 32
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. size
2
Removed Element = 32
Queue = Empty
Do you want to continue (Type y or n)
y
Queue Operations
1. insert
2. remove
3. peek
4. check empty
5. check full
6. 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. check full
6. size
4
Empty status = true
Queue = Empty
Do you want to continue (Type y or n)
n
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