Merge pull request #21 from FarazRashid/main

Implemented the circular queue

C++/CircularQueue.cpp

@@ -0,0 +1,119 @@
+#include <iostream>
+using namespace std;
+
+#define MAX_SIZE 5
+
+class CircularQueue {
+private:
+    int* arr;
+    int maxSize;
+    int front, rear;
+
+public:
+    // Constructor initializes front and rear to -1 indicating an empty queue
+     CircularQueue(int size) : maxSize(size), front(-1), rear(-1) {
+        arr = new int[maxSize];
+    }
+
+    // Function to check if the queue is empty
+    bool isEmpty() {
+        return (front == -1 && rear == -1);
+    }
+
+    // Function to check if the queue is full
+    bool isFull() {
+        return (front == (rear + 1) % MAX_SIZE);
+    }
+
+    // Function to enqueue an element to the queue
+    void enqueue(int item) {
+        if (isFull()) {
+            cout << "Queue is full. Cannot enqueue element." << endl;
+        } else {
+            // If the queue is empty, set front and rear to 0
+            if (isEmpty()) {
+                front = rear = 0;
+            } else {
+                // Circularly increment rear index
+                rear = (rear + 1) % MAX_SIZE;
+            }
+            arr[rear] = item;
+            cout << item << " enqueued to the queue." << endl;
+        }
+    }
+
+    // Function to dequeue an element from the queue
+    void dequeue() {
+        if (isEmpty()) {
+            cout << "Queue is empty. Cannot dequeue element." << endl;
+        } else {
+            int removedItem = arr[front];
+            // If there is only one element in the queue, reset front and rear to -1
+            if (front == rear) {
+                front = rear = -1;
+            } else {
+                // Circularly increment front index
+                front = (front + 1) % MAX_SIZE;
+            }
+            cout << removedItem << " dequeued from the queue." << endl;
+        }
+    }
+
+    // Function to display the elements in the queue
+    void display() {
+        if (isEmpty()) {
+            cout << "Queue is empty." << endl;
+        } else {
+            int i = front;
+            cout << "Queue: ";
+            // Loop through the queue elements using circular index calculation
+            do {
+                cout << arr[i] << " ";
+                i = (i + 1) % MAX_SIZE;
+            } while (i != (rear + 1) % MAX_SIZE);
+            cout << endl;
+        }
+    }
+
+    // Destructor to release dynamically allocated memory
+    ~CircularQueue() {
+        delete[] arr;
+    }
+
+};
+
+// Driver program
+int main() {
+    int maxSize;
+    cout << "Enter the maximum size of the circular queue: ";
+    cin >> maxSize;
+
+    CircularQueue queue(maxSize);
+
+    // Enqueue elements to the queue
+    queue.enqueue(1);
+    queue.enqueue(2);
+    queue.enqueue(3);
+    queue.display(); // Queue: 1 2 3
+
+    // Dequeue an element and display the queue
+    queue.dequeue();
+    queue.display(); // Queue: 2 3
+
+    // Enqueue more elements
+    queue.enqueue(4);
+    queue.enqueue(5);
+    queue.display(); // Queue: 2 3 4 5
+
+    // Attempt to enqueue when the queue is full
+    queue.enqueue(6); // Queue is full, cannot enqueue 6
+
+    // Dequeue all elements from the queue
+    queue.dequeue();
+    queue.dequeue();
+    queue.dequeue();
+    queue.dequeue();
+    queue.dequeue(); // Queue is empty, cannot dequeue further
+
+    return 0;
+}