diff --git a/stacks_queues/queue.py b/stacks_queues/queue.py index d66dab2..5549a47 100644 --- a/stacks_queues/queue.py +++ b/stacks_queues/queue.py @@ -1,11 +1,13 @@ +from sqlalchemy import null + INITIAL_QUEUE_SIZE = 20 class QueueFullException(Exception): pass class QueueEmptyException(Exception): - pass + pass class Queue: @@ -23,34 +25,54 @@ def enqueue(self, element): In the store are occupied returns None """ - pass + + if self.front == (self.rear + 1) % self.buffer_size: + raise QueueFullException() + + if self.front == -1: + self.front = 0 + + self.rear = (self.rear +1) % self.buffer_size + self.store[self.rear] = element + self.size += 1 def dequeue(self): """ Removes and returns an element from the Queue Raises a QueueEmptyException if The Queue is empty. """ - pass + + if self.front == -1: + raise QueueEmptyException() + else: + element = self.store[self.front] + self.front = (self.front + 1) % self.buffer_size + self.size -= 1 + + return element def front(self): """ Returns an element from the front of the Queue and None if the Queue is empty. Does not remove anything. """ - pass - + if self.size == 0: + return None + + return self.store[self.front] def size(self): """ Returns the number of elements in The Queue """ - pass + return self.size def empty(self): """ Returns True if the Queue is empty And False otherwise. """ - pass + return self.size == 0 + def __str__(self): """ Returns the Queue in String form like: @@ -58,4 +80,19 @@ def __str__(self): Starting with the front of the Queue and ending with the rear of the Queue. """ - pass + + queue_list = [] + + if self.size == 0: + return queue_list + + current = self.front + + while current != self.rear: + if current != None: + queue_list.append(self.store[current]) + current = (current + 1) % self.buffer_size + + queue_list.append(self.store[self.rear]) + + return str(queue_list) \ No newline at end of file diff --git a/stacks_queues/stack.py b/stacks_queues/stack.py index 94fb2a6..fb8da6a 100644 --- a/stacks_queues/stack.py +++ b/stacks_queues/stack.py @@ -12,7 +12,8 @@ def push(self, element): """ Adds an element to the top of the Stack. Returns None """ - pass + self.store.add_first(element); + return None def pop(self): """ Removes an element from the top @@ -21,13 +22,15 @@ def pop(self): The Stack is empty. returns None """ - pass + if not self.empty(): + return self.store.remove_first() def empty(self): """ Returns True if the Stack is empty And False otherwise """ - pass + + return self.store.empty() def __str__(self): """ Returns the Stack in String form like: @@ -35,4 +38,4 @@ def __str__(self): Starting with the top of the Stack and ending with the bottom of the Stack. """ - pass + return str(self.store)