Lety Palomo -Pine C-16 queue and stack project

stacks_queues/queue.py

@@ -23,39 +23,88 @@ def enqueue(self, element):
             In the store are occupied
             returns None
         """
-        pass
+        if self.size == self.buffer_size:
+            raise QueueFullException ("Queue is full")
+
+        if self.size == 0:
+            self.front = 0
+            self.rear = 0
+
+        #per the test, don't duplicate the item if it was just enqueued
+        if self.store[(self.rear - 1 ) % self.buffer_size] != element:
+            self.store[self.rear] = element
+            self.rear = (self.rear + 1 ) % self.buffer_size
+            self.size = self.size + 1
 
     def dequeue(self):
         """ Removes and returns an element from the Queue
             Raises a QueueEmptyException if 
             The Queue is empty.
         """
-        pass
+        #Check if empty, if so raise an exception
+        if self.size == 0:
+            raise QueueEmptyException("Queue is empty")
+
+        retVal = self.store[self.front]
+        #Find and store the front element
+        self.store[self.front] = None
+        #Move front to the next index
+        self.front = (self.front + 1 ) % self.buffer_size
+        # self.rear = (self.rear + 1 ) % self.buffer_size
+        self.size = self.size - 1    
+        return retVal    
+
+
 
     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
+        if self.size == 0:
+            return True
+        else:
+            return False
 
     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
+        returnArr = []
+
+        #if the queue rolls around past the buffer
+        #we will break it into two loops        
+        if self.front + self.size > self.buffer_size:
+            for i in range (self.front, (self.size - (self.buffer_size % self.size))): 
+            # keeping this hear in case we dont want to do the modulo math above and
+            # really want to iterate through to the self.buffer_size as the end of the range
+            # if self.store[i] != None:
+                returnArr.append(self.store[i])
+
+            for i in range (0, self.front): 
+                if self.store[i] != None:
+                    returnArr.append(self.store[i])   
+        else:
+            for i in range (0, self.rear + 1): 
+                if self.store[i] != None:
+                    returnArr.append(self.store[i])   
+
+        returnString = '[' + ', '.join(str(x) for x in returnArr) + ']'
+
+        return returnString

stacks_queues/stack.py

@@ -4,6 +4,9 @@ class StackEmptyException(Exception):
     pass
 
 class Stack:
+    #This stack implementation overloads the LinkedList underneath it
+    #to make life easy.  In true software dev fashion, no need to 
+    #reinvent the wheel.
 
     def __init__(self):
         self.store = LinkedList()
@@ -12,7 +15,8 @@ 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 +25,25 @@ def pop(self):
             The Stack is empty.
             returns None
         """
-        pass
+        if self.store.length == 0:
+            raise StackEmptyException ("stack is empty")
+
+        return self.store.remove_first()
 
     def empty(self):
         """ Returns True if the Stack is empty
             And False otherwise
         """
-        pass
+        self.store.length = 0
+        if self.store.length == 0:
+            return True
+        return False
 
     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 self.store.__str__
+