Add queue

Author: mcleber

src/queue.cpp

@@ -0,0 +1,153 @@
+#include <iostream>
+#include <string>
+
+#define SIZE 10 // Define the size of the queue
+
+// FIFO: First In - First Out
+
+// Function prototypes
+void PrintQueue(int queue[SIZE], int size);
+void QueueConstructor(int *front, int *rear);
+bool IsQueueEmpty(int front, int rear);
+bool IsQueueFull(int rear);
+void Enqueue(int queue[SIZE], int value, int *rear);
+void Dequeue(int queue[SIZE], int *front, int rear);
+int QueueSize(int rear, int front);
+
+int main()
+{
+    // Initialize variables
+    setlocale(LC_ALL, "en-US");
+
+    int front, rear, value;
+    int queue[SIZE] = {0}; // Initialize the queue with zeros
+
+    // Set up the queue with initial values for front and rear
+    QueueConstructor(&front, &rear);
+
+    // Enqueue some values
+    Enqueue(queue, 5, &rear);
+    Enqueue(queue, 7, &rear);
+
+    // Dequeue and print values
+    Dequeue(queue, &front, rear);
+    Dequeue(queue, &front, rear);
+    Dequeue(queue, &front, rear);
+
+    // Enqueue a new value
+    Enqueue(queue, 8, &rear);
+
+    // Print the current queue and its size
+    PrintQueue(queue, QueueSize(rear, front));
+
+    std::cout << std::endl;
+    system("PAUSE");
+    return 0;
+}
+
+/**
+ * Prints the current state of the queue.
+ *
+ * @param queue The queue array.
+ * @param size The size of the queue.
+ */
+void PrintQueue(int queue[SIZE], int size)
+{
+    // Print each element in the queue, followed by a separator
+    for (int i = 0; i < SIZE; ++i)
+    {
+        std::cout << queue[i] << " - ";
+    }
+    std::cout << std::endl;
+}
+
+/**
+ * Initializes the queue with the front at 0 and the rear at -1.
+ *
+ * @param front A pointer to the front index of the queue.
+ * @param rear A pointer to the rear index of the queue.
+ */
+void QueueConstructor(int *front, int *rear)
+{
+    *front = 0; // Set the front pointer to 0
+    *rear = -1; // Set the rear pointer to -1, indicating an empty queue
+}
+
+/**
+ * Checks if the queue is empty.
+ *
+ * @param front The front index of the queue.
+ * @param rear The rear index of the queue.
+ * @return True if the queue is empty, otherwise false.
+ */
+bool IsQueueEmpty(int front, int rear)
+{
+    return front > rear; // Queue is empty if front index is greater than rear
+}
+
+/**
+ * Checks if the queue is full.
+ *
+ * @param rear The rear index of the queue.
+ * @return True if the queue is full, otherwise false.
+ */
+bool IsQueueFull(int rear)
+{
+    return rear == SIZE - 1; // Queue is full if rear reaches the last index
+}
+
+/**
+ * Adds a value to the queue (enqueue operation).
+ *
+ * @param queue The queue array.
+ * @param value The value to be added to the queue.
+ * @param rear A pointer to the rear index of the queue.
+ */
+void Enqueue(int queue[SIZE], int value, int *rear)
+{
+    // Check if the queue is full
+    if (IsQueueFull(*rear))
+    {
+        std::cout << "Queue is full.\n";
+    }
+    else
+    {
+        *rear = *rear + 1;    // Increment the rear pointer
+        queue[*rear] = value; // Place the value at the rear of the queue
+    }
+}
+
+/**
+ * Removes a value from the queue (dequeue operation).
+ *
+ * @param queue The queue array.
+ * @param front A pointer to the front index of the queue.
+ * @param rear The rear index of the queue.
+ */
+void Dequeue(int queue[SIZE], int *front, int rear)
+{
+    // Check if the queue is empty
+    if (IsQueueEmpty(*front, rear))
+    {
+        std::cout << "\nUnable to dequeue from an empty queue.\n";
+    }
+    else
+    {
+        // Print the value that is dequeued
+        std::cout << "\nValue " << queue[*front] << " was removed.\n";
+        queue[*front] = 0;   // Set the dequeued position to 0 (optional)
+        *front = *front + 1; // Increment the front pointer
+    }
+}
+
+/**
+ * Returns the current size of the queue.
+ *
+ * @param rear The rear index of the queue.
+ * @param front The front index of the queue.
+ * @return The current size of the queue.
+ */
+int QueueSize(int rear, int front)
+{
+    return (rear - front) + 1; // The size of the queue is the difference between rear and front
+}