A queue is a linear data structure that follows the First-In-First-Out (FIFO) principle. Elements are inserted at the back(rear) and deleted from the front. In this blog post, we’ll explore how to implement a queue data structure in C++.
Table of Contents
Introduction to Queue
A queue is similar to a real-life queue, such as people waiting in line for their turn. The element which is inserted first is the first one to be removed. It follows the FIFO (First-In-First-Out) order and provides operations like enqueue and dequeue.
Implementing Queue in C++
#include <iostream>
#define MAX_SIZE 100
class Queue {
private:
int arr[MAX_SIZE];
int front;
int rear;
public:
Queue() {
front = -1;
rear = -1;
}
bool isEmpty() {
return (front == -1 && rear == -1);
}
bool isFull() {
return (rear == MAX_SIZE - 1);
}
void enqueue(int value) {
if (isFull()) {
std::cout << "Queue is full. Cannot enqueue." << std::endl;
return;
} else if (isEmpty()) {
front = 0; // Set front to 0 when enqueueing the first element
}
arr[++rear] = value;
}
void dequeue() {
if (isEmpty()) {
std::cout << "Queue is empty. Cannot dequeue." << std::endl;
return;
} else if (front == rear) {
// Reset front and rear to -1 when dequeueing the last element
front = -1;
rear = -1;
} else {
front++;
}
}
void display() {
if (isEmpty()) {
std::cout << "Queue is empty." << std::endl;
return;
}
std::cout << "Queue: ";
for (int i = front; i <= rear; i++) {
std::cout << arr[i] << " ";
}
std::cout << std::endl;
}
};
int main() {
Queue queue;
queue.enqueue(10);
queue.enqueue(20);
queue.enqueue(30);
queue.enqueue(40);
queue.dequeue();
queue.display();
return 0;
}
Queue Operations
The implemented queue data structure supports the following operations:
enqueue(value): Inserts the given value at the rear end of the queue.dequeue(): Removes the element from the front of the queue.isEmpty(): Returns true if the queue is empty, and false otherwise.isFull(): Returns true if the queue is full, and false otherwise.display(): Prints the elements of the queue.
Conclusion
Implementing a queue data structure in C++ is straightforward and can be useful in various scenarios. By understanding the operations and how they work together, you can effectively use queues in your programs for efficient data processing.
#programming #datastructure