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Queue Enqueue Operations
Introduction to Enqueue:
The enqueue operation adds an element to the rear of the queue. It follows the First-In-First-Out (FIFO) principle, where the first element added is the first to be removed.
// Queue Enqueue Operation Example
public class Queue {
private int front, rear, capacity;
private int queue[];
Queue(int c) {
front = rear = 0;
capacity = c;
queue = new int[capacity];
}
void enqueue(int data) {
if (capacity == rear) {
System.out.println("Queue is full");
return;
} else {
queue[rear] = data;
rear++;
}
}
void display() {
if (front == rear) {
System.out.println("Queue is empty");
return;
}
for (int i = front; i < rear; i++) {
System.out.print(queue[i] + " ");
}
System.out.println();
}
}
Example 1: Adding Elements
When you enqueue elements 10, 20, and 30, they are added to the queue in the order they are received. The queue becomes [10, 20, 30].
Queue q = new Queue(5);
q.enqueue(10);
q.enqueue(20);
q.enqueue(30);
q.display(); // Output: 10 20 30
Example 2: Queue Overflow
Attempting to enqueue more elements than the queue can hold results in a "Queue is full" message.
q.enqueue(40);
q.enqueue(50);
q.enqueue(60); // Output: Queue is full
Example 3: Circular Queue Concept
In a circular queue, once the rear reaches the end, it wraps around to the beginning if there is space.
// Assuming a circular queue implementation
q.enqueue(70);
q.dequeue();
q.enqueue(80); // Rear wraps around if space is available
q.display(); // Output: 20 30 70 80
Example 4: Enqueue in a Dynamic Queue
A dynamic queue can grow as needed, avoiding overflow.
// Assuming a dynamic queue implementation
DynamicQueue dq = new DynamicQueue();
dq.enqueue(90);
dq.enqueue(100);
dq.enqueue(110);
dq.display(); // Output: 90 100 110
Example 5: Enqueue with Priority
In a priority queue, elements are enqueued based on priority rather than order of arrival.
PriorityQueue pq = new PriorityQueue();
pq.enqueue(15, 2); // Element 15 with priority 2
pq.enqueue(25, 1); // Element 25 with priority 1
pq.display(); // Output: 25 15 (25 has higher priority)
