Lec-12, 13 Quees A class for Dynamic Queue implementation
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The document outlines the implementation of a dynamic integer queue using a linked list structure in C++. It includes class definitions for the queue, node structure, and methods for enqueueing, dequeueing, checking if the queue is empty, and clearing the queue. A sample program demonstrates how to use the queue class by enqueuing five items and then dequeuing them.
Lec-12, 13 Quees A class for Dynamic Queue implementation
- 1. A class for Dynamic Queue implementation class DynIntQueue { private: struct QueueNode { int value; QueueNode *next; }; QueueNode *front; QueueNode *rear; int numItems; public: DynIntQueue(void); ~DynIntQueue(void); void enqueue(int); int dequeue(void); bool isEmpty(void); void makeNull(void); };
- 2. Implemenaton //************************ // Constructor * //************************ DynIntQueue::DynIntQueue(void) { front = NULL; rear = NULL; numItems = 0; } //************************ // Destructor * //************************ DynIntQueue::~DynIntQueue(void) { makeNull(); }
- 3. //******************************************** // Function enqueue inserts the value in num * // at the rear of the queue. * //******************************************** void DynIntQueue::enqueue(int num) { QueueNode *newNode; newNode = new QueueNode; newNode->value = num; newNode->next = NULL; if (isEmpty()) { front = newNode; rear = newNode; } else { rear->next = newNode; rear = newNode; } numItems++; }
- 4. //********************************************** // Function dequeue removes the value at the * // front of the queue, and copies it into num. * //********************************************** int DynIntQueue::dequeue(void) { QueueNode *temp; int num; if (isEmpty()) cout << "The queue is empty.n"; else { num = front->value; temp = front->next; delete front; front = temp; numItems--; } return num; }
- 5. //********************************************* // Function isEmpty returns true if the queue * // is empty, and false otherwise. * //********************************************* bool DynIntQueue::isEmpty(void) { if (numItems) return false; else return true; }
- 6. //******************************************** // Function makeNull dequeues all the elements * // in the queue. * //******************************************** void DynIntQueue::makeNull(void) { while(!isEmpty()) dequeue(); }
- 7. Program // This program demonstrates the DynIntQeue class void main(void) { DynIntQueue iQueue; cout << "Enqueuing 5 items...n"; // Enqueue 5 items. for (int x = 0; x < 5; x++) iQueue.enqueue(x); // Deqeue and retrieve all items in the queue cout << "The values in the queue were:n"; while (!iQueue.isEmpty()) { int value; value =iQueue.dequeue(); cout << value << endl; } }
- 8. Program Ouput Enqueuing 5 items... The values in the queue were: 0 1 2 3 4
Editor's Notes
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