Data Structure and Algorithms : Queue Program in Java

Program:

public class queuepgm {
private int maxSize;
private long[] queArray;
private int front;
private int rear;
private int nItems;

public queuepgm(int s)

{
maxSize = s;
queArray = new long[maxSize];
front = 0;
rear = -1;
nItems = 0;
}

public void enqueue(long j)

{
if(rear == maxSize-1)
rear = -1;
queArray[++rear] = j;
nItems++;
}

public long dequeue()
{
long temp = queArray[front++];
if(front == maxSize)
front = 0;
nItems--;
return temp;
}
public long peekFront()

{
    return queArray[front];
}
public boolean isEmpty()      
{
return (nItems==0);
}
public boolean isFull()
{
return (nItems==maxSize);
}
public int size()
{
return nItems;
}
public static void main(String[] args)
{
queuepgm theQueue = new queuepgm(5); // queue holds 5 items
theQueue.enqueue(10);
theQueue.enqueue(20);
theQueue.enqueue(30);
theQueue.enqueue(40);
System.out.println("Dequeue Values: FIFO");
while( !theQueue.isEmpty() )
{
long n = theQueue.dequeue();
System.out.print(n+"\n");

}
}

}

Output: