Data Abstraction and Problem Solving with C++
Walls and Mirrors
by Frank M. Carrano
QueueA.cpp
Go to the documentation of this file.00001 00021 #include "QueueA.h" // header file 00022 00023 Queue::Queue() : front(0), back(MAX_QUEUE-1), count(0) 00024 { 00025 } // end default constructor 00026 00027 bool Queue::isEmpty() const 00028 { 00029 return count == 0; 00030 } // end isEmpty 00031 00032 void Queue::enqueue(const QueueItemType& newItem) 00033 throw(QueueException) 00034 { 00035 if (count == MAX_QUEUE) 00036 throw QueueException( 00037 "QueueException: queue full on enqueue"); 00038 else 00039 { // queue is not full; insert item 00040 back = (back+1) % MAX_QUEUE; 00041 items[back] = newItem; 00042 ++count; 00043 } // end if 00044 } // end enqueue 00045 00046 void Queue::dequeue() throw(QueueException) 00047 { 00048 if (isEmpty()) 00049 throw QueueException( 00050 "QueueException: empty queue, cannot dequeue"); 00051 else 00052 { // queue is not empty; remove front 00053 front = (front+1) % MAX_QUEUE; 00054 --count; 00055 } // end if 00056 } // end dequeue 00057 00058 void Queue::dequeue(QueueItemType& queueFront) 00059 throw(QueueException) 00060 { 00061 if (isEmpty()) 00062 throw QueueException( 00063 "QueueException: empty queue, cannot dequeue"); 00064 else 00065 { // queue is not empty; retrieve and remove front 00066 queueFront = items[front]; 00067 front = (front+1) % MAX_QUEUE; 00068 --count; 00069 } // end if 00070 } // end dequeue 00071 00072 void Queue::getFront(QueueItemType& queueFront) const 00073 throw(QueueException) 00074 { 00075 if (isEmpty()) 00076 throw QueueException( 00077 "QueueException: empty queue, cannot getFront"); 00078 else 00079 // queue is not empty; retrieve front 00080 queueFront = items[front]; 00081 } // end getFront 00082 // End of implementation file.
