Al Leonard - Completed assignement with all tests passing.

stacks_queues/linked_list.py

@@ -48,7 +48,7 @@ def remove_first(self):
 
 
     def empty(self):
-      return not self.head
+        return not self.head
 
     # method to find if the linked list contains a node with specified value
     # returns true if found, false otherwise

stacks_queues/queue.py

@@ -1,4 +1,3 @@
-
 INITIAL_QUEUE_SIZE = 20
 
 class QueueFullException(Exception):
@@ -15,48 +14,78 @@ 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.rear + 1) % self.buffer_size == self.front):
+            raise QueueFullException("Queue full")
+        elif self.empty():
+            self.front = 0
+            self.rear = 0
+            self.store[self.rear] = element
+        else:
+            self.rear = (self.rear + 1) % self.buffer_size
+            self.store[self.rear] = element
 
     def dequeue(self):
         """ Removes an element from the Queue
-            Raises a QueueEmptyException if 
+            Raises a QueueEmptyException if
             The Queue is empty.
             returns None
         """
-        pass
+        if self.empty():
+            raise QueueEmptyException('Queue is empty.')
+
+        data = self.store[self.front]
+        self.store[self.front] = None
+
+        if (self.front == self.rear):
+            self.front = -1
+            self.rear = -1
+        else:
+            self.front = (self.front + 1) % self.buffer_size
+        return data
 
     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.empty():
+            return None
+        return self.store[self.front]
 
     def size(self):
         """ Returns the number of elements in
             The Queue
         """
-        pass
+        size = self.__str__().count(",") + 1
+        return size
 
     def empty(self):
         """ Returns True if the Queue is empty
             And False otherwise.
         """
-        pass
+        return self.front == -1
 
     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
+        if self.empty():
+            return "[]"
+
+        q = []
+        front = self.front
+        while front != self.rear:
+            q.append(self.store[front])
+            front += 1
+            front %= self.buffer_size
+        q.append(self.store[self.rear])
+        return str(q)

stacks_queues/stack.py

@@ -1,18 +1,20 @@
-from stacks_queues.linked_list import LinkedList
+# from stacks_queues.linked_list import LinkedList
 
 class StackEmptyException(Exception):
     pass
 
 class Stack:
-
     def __init__(self):
-        self.store = LinkedList()
+        # self.store = LinkedList()
+        self.st = []
 
     def push(self, element):
         """ Adds an element to the top of the Stack.
             Returns None
         """
-        pass
+        # self.store.add_first(item)
+        self.st.append(element)
+
 
     def pop(self):
         """ Removes an element from the top
@@ -21,18 +23,23 @@ def pop(self):
             The Stack is empty.
             returns None
         """
-        pass
+        # return self.store.remove_first()
+        if (len(self.st)>0):
+            result = self.st.pop()
+            return result
 
     def empty(self):
         """ Returns True if the Stack is empty
             And False otherwise
         """
-        pass
+        # return self.store.length() == 0
+        return len(self.st) == 0
 
     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)
+        return str(self.st)