c07p359.txt

Data Abstraction & Problem Solving with C++源码

template <class T, class Container = deque <T> >
class queue
{
public:
   explicit queue(const Container& cnt = Container());
   // Default constructor, initializes an empty queue.
   // Precondition: None.
   // Postcondition: An empty queue exists.

   bool empty() const;
   // Determines if the queue is empty.
   // Precondition: None.
   // Postcondition: Returns true if the queue is empty, 
   // otherwise returns false.

   size_type size() const;
   // Determines the size of the queue. size_type is
   // an integral type.
   // Precondition: None.
   // Postcondition: Returns the number of items that 
   // are currently in the queue.

   T &front();
   // Returns a reference to the first item in the queue.
   // Precondition: None.
   // Postcondition: The item is not removed from the queue.

   T &back();
   // Returns a reference to the last item in the queue.
   // Precondition: None.
   // Postcondition: The item is not removed from the queue.
   void pop();
   // Removes the first item in the queue.
   // Precondition: None.
   // Postcondition: The item at the front of the queue is 
   // removed.

   void push(const T& x);
   // Inserts an item at the back of the queue.
   // Precondition: None.
   // Postcondition: The item x is at the back of the queue.

} // end STL queue