Pine - Kris J

stacks_queues/queue.py

@@ -1,4 +1,3 @@
-
 INITIAL_QUEUE_SIZE = 20
 
 class QueueFullException(Exception):
@@ -15,47 +14,74 @@ def __init__(self):
         self.front = -1
         self.rear = -1
         self.size = 0
-      
+
 
     def enqueue(self, element):
         """ Adds an element to the Queue
             Raises a QueueFullException if all elements
             In the store are occupied
             returns None
         """
-        pass
+        if self.front == -1:
+            self.front = 0
+            self.rear = 0
+        elif self.rear == self.front:
+            raise QueueFullException("Queue is full!")
 
+        self.store[self.rear] = element
+        self.rear = (self.rear + 1) % self.buffer_size
+        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.size == 0:
+            raise QueueEmptyException('Queue is empty')
+
+        element = self.store[self.front]
+        self.store[self.front] = None 
+        self.front = (self.front + 1) % self.buffer_size
+        if self.front == self.rear:
+            self.front = -1
+            self.rear = -1
+        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
+        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:
             [3, 4, 7]
             Starting with the front of the Queue and
             ending with the rear of the Queue.
         """
-        pass
+        result = ""
+        num = 0
+        curr = self.front
+        while num < self.size:
+            result += str(self.store[curr]) + ", "
+            curr = (curr + 1) % self.buffer_size
+            num += 1
+
+        return "[" + result[:-2] + "]"

stacks_queues/stack.py

@@ -12,7 +12,7 @@ def push(self, element):
         """ Adds an element to the top of the Stack.
             Returns None
         """
-        pass
+        return self.store.add_first(element)
 
     def pop(self):
         """ Removes an element from the top
@@ -21,18 +21,18 @@ def pop(self):
             The Stack is empty.
             returns None
         """
-        pass
+        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:
             [3, 4, 7]
             Starting with the top of the Stack and
             ending with the bottom of the Stack.
         """
-        pass
+        return str(self.store)