Playing with templates

Submitted by mapleman on Mon, 2008-05-19 18:13

Dumb strokes of C++ templates while bored generated this templated queue.

  1. #define QueueSize 5
  2.  
  3. template <typename T>
  4. class Queue
  5. {
  6.  
  7. public:
  8. 	Queue() : head(NULL), tail(-1) { for (int i=0; i < QueueSize; queue[i++]=NULL); }
  9.  	void insert(T in);
  10.  	bool isEmpty() { return ( queue[head] == NULL ) ? true : false; }
  11.  	bool isFull() { return (head == tail && queue[head] != NULL) ? true : false; }	
  12.  	T remove();
  13.  	void showContents();
  14.  
  15. private:
  16.  	T queue[QueueSize];
  17.  	int head, tail;
  18.  
  19. };
  20.  
  21. template <typename T> 
  22. void Queue<T>::showContents()
  23. {
  24.  
  25.  	int loc=0, i=0;
  26.  
  27.  	if(isEmpty())
  28.  	{
  29.  		cout << "Empty" << endl;
  30.  		return;
  31. 	}
  32.  
  33.  
  34.  	for (i=head; i < tail || i < QueueSize;  i++)
  35.  		cout << queue[i] << " ";	
  36.  
  37.  	if(head > loc)
  38.  		while(loc < tail && loc < head && queue[loc] != NULL)
  39.  			cout << queue[loc++] << " ";
  40.  
  41.  	cout << endl;
  42.  
  43.  
  44.  }
  45.  
  46.  
  47.  template <typename T> 
  48.  T Queue<T>::remove() 
  49.  {  
  50.  	int retVal = 0;	
  51.  
  52.  	if (!isEmpty())
  53.  	{
  54.  
  55.  		retVal = queue[head];			
  56.  		queue[head] = NULL;
  57.  
  58.  		if (head == QueueSize - 1)
  59.  			head = 0;
  60.  		else
  61.  			head++;			
  62.  
  63.  	}
  64.  	else
  65.  		cout << "Stack Underflow" << endl;
  66.  
  67.  	return retVal;
  68.  
  69.  }
  70.  
  71.  template <typename T>
  72.  void Queue<T>::insert(T in)
  73.  {	
  74.  	int prevTail = tail;
  75.  
  76.  	if (tail == QueueSize - 1)
  77.  		tail = 0;
  78.  	else
  79.  		tail++;
  80.  
  81.  
  82.  	if (isFull())
  83.  	{
  84.  		cout << "Stack Overflow" << endl;	
  85.  		tail = prevTail;
  86.  	}
  87.  	else
  88.  		queue[tail] = in;
  89.  
  90.  
  91.  	return;
  92.  }

Tags: