1   // Fig. 15.12: queue.h
2   // Queue class template definition
3   // Derived from class List
4   #ifndef QUEUE_H
5   #define QUEUE_H
6   
7   #include "list.h"
8   
9   template< class QUEUETYPE >
10  class Queue: private List< QUEUETYPE > {
11  public:
12     void enqueue( const QUEUETYPE &d ) { insertAtBack( d ); }
13     bool dequeue( QUEUETYPE &d ) 
14        { return removeFromFront( d ); }
15     bool isQueueEmpty() const { return isEmpty(); }
16     void printQueue() const { print(); }
17  };
18  
19  #endif
20  
21  
22  // Fig. 15.12: fig15_12.cpp
23  // Driver to test the template Queue class
24  #include <iostream.h>
25  #include "queue.h"
26  
27  int main()
28  {
29     Queue< int > intQueue;
30     int dequeueInteger;
31     cout << "processing an integer Queue" << endl;
32  
33     for ( int i = 0; i < 4; i++ ) {
34        intQueue.enqueue( i );
35        intQueue.printQueue();
36     }
37  
38     while ( !intQueue.isQueueEmpty() ) {
39        intQueue.dequeue( dequeueInteger );
40        cout << dequeueInteger << " dequeued" << endl;
41        intQueue.printQueue();
42     }
43  
44     Queue< double > doubleQueue;
45     double val = 1.1, dequeuedouble;
46  
47     cout << "processing a double Queue" << endl;
48  
49     for ( i = 0; i < 4; i++ ) {
50        doubleQueue.enqueue( val );
51        doubleQueue.printQueue();
52        val += 1.1;
53     }
54  
55     while ( !doubleQueue.isQueueEmpty() ) {
56        doubleQueue.dequeue( dequeuedouble );
57        cout << dequeuedouble << " dequeued" << endl;
58        doubleQueue.printQueue();
59     }
60  
61     return 0;
62  }