Question

Consider the following statements: queueType queue; int num; Show what is output by the following segment of code: num = 7; queue.addQueue(6); queue.addQueue(num); num = queue.front(); queue.deleteQueue(); queue.addQueue(num + 5); queue.addQueue(14); queue.addQueue(num - 2); queue.addQueue(25); queue.deleteQueue(); cout << "Queue elements: "; while (!queue.isEmptyQueue()) { cout << queue.front() << " "; queue.deleteQueue(); } cout << endl;

Short answer

The output is 'Queue elements: 11 14 4 25'.

Step-by-step solution

Initialize and Add Elements to Queue

Start with an empty queue and initialize `num` to 7. The code `queue.addQueue(6);` adds 6 to the queue. Then `queue.addQueue(num);` adds 7 to the queue. At this point, the queue contains: [6, 7].

Modify `num` and Update Queue

Set `num` to the front of the queue with `num = queue.front();`, so `num` becomes 6. Then `queue.deleteQueue();` removes the first element (6) from the queue. The queue now contains: [7].

Add Calculated Elements to Queue

Add `num + 5` (which is 11) to the queue using `queue.addQueue(num + 5);`, so the queue becomes: [7, 11]. Then `queue.addQueue(14);` adds 14, making the queue: [7, 11, 14].

Further Queue Modifications

Add `num - 2` (which is 4) to the queue with `queue.addQueue(num - 2);` changing the queue to: [7, 11, 14, 4]. Then `queue.addQueue(25);` adds 25, so the queue is now: [7, 11, 14, 4, 25].

Remove and Display Queue Elements

Remove the first element with `queue.deleteQueue();`, resulting in the queue: [11, 14, 4, 25]. The loop iterates through each element, displaying and deleting it, resulting in the output 'Queue elements: 11 14 4 25'. Once empty, the loop ends.

Key concepts

Queue Operations

In a queue data structure, elements follow a "First In, First Out" (FIFO) approach. This means the first element added is the first one to be removed. Basic queue operations include adding, removing, and accessing elements.

- **Enqueue (addQueue)**: This operation adds an item to the back of the queue. In the given exercise, the initial enqueuing places the numbers 6 and 7 into the queue, creating the sequence [6, 7]. - **Dequeue (deleteQueue)**: This operation removes the item from the front of the queue. After 6 is dequeued, only 7 remains.

- **Peek (front)**: This operation views the front element without removing it. When `num` is assigned to `queue.front()`, it retrieves the front element. These operations are essential for managing the order of elements efficiently, ensuring that changes to the queue maintain the correct sequence as processing proceeds.

C++ Programming

When utilizing queues in C++ programming, understanding object creation and method calls is key. The queue implementation depends on classes, encapsulating queue operations.

- **Class Initialization**: A queue object is declared as `queueType queue;`, specifying it will handle integers. This ensures that all members, such as adding or removing elements, will operate on integer values. - **Methods**: The class provides methods like `addQueue()`, `deleteQueue()`, and `isEmptyQueue()`. Each method is essential for manipulating the queue within the program's logic. C++ incorporates these structures by binding data with functions. It allows the queue to exhibit behavior through member methods, enabling controlled access to the queue's contents.

Algorithm Implementation

Implementing an algorithm with queues requires precise management of operations sequentially. The goal is to maintain order while applying logic like conditional checks and arithmetic operations.

Consider the steps in the exercise: - **Initialize and Modify**: The queue starts with numbers 6 and 7, influenced by `num`, which later changes based on queue operations. - **Apply Logic**: Logical operations are performed, such as `queue.addQueue(num + 5)`, enhancing the queue to include calculated values. In this setup, arithmetic calculations maintain logical flow. - **Iterative Display**: A `while` loop checks if the queue is empty with `queue.isEmptyQueue()`. This loop fetches and prints each element until the queue is exhausted, ensuring a systematic display of all processed numbers. The implementation encapsulates queue handling logic, ensuring each step works coherently towards the final output, with intricate handling of data through logic and structural elements.