Scissors - Aida R.

stacks_queues/queue.py

@@ -15,47 +15,86 @@ 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.size == 0:
+            self.front = 0
+
+        elif self.size == self.buffer_size:
+            raise QueueFullException("Error message")
+
+        self.rear = (self.rear + 1) % self.buffer_size
+        self.store[self.rear] = element
+        self.size += 1
+        return None
 
     def dequeue(self):
         """ Removes and returns an element from the Queue
             Raises a QueueEmptyException if 
             The Queue is empty.
         """
-        pass
+        try:
+            temp = self.store[self.front]
+            self.store[self.front] = None
+            self.front = (self.front + 1) % self.buffer_size
+            self.size -= 1
+            return temp
+        except:
+            raise QueueEmptyException("Error message")
 
     def front(self):
         """ Returns an element from the front
             of the Queue and None if the Queue
             is empty.  Does not remove anything.
         """
-        pass
-
+        try:
+            return self.store[self.front]
+        except:
+            raise QueueEmptyException("Error message")
 
     def size(self):
         """ Returns the number of elements in
             The Queue
         """
-        pass
+        try:
+            return self.size
+        except:
+            raise QueueEmptyException("Error message")
+
 
     def empty(self):
         """ Returns True if the Queue is empty
             And False otherwise.
         """
-        pass
+        try:
+            return self.size == 0
+        except:
+            raise QueueEmptyException("Error message")
 
     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
+        nodes = []
+        back = self.rear
+
+        if self.size == 0:
+            return nodes
+
+        current = self.front
+
+        while current != back:
+            nodes.append(self.store[current])
+            current = (current + 1) % self.buffer_size
+
+        nodes.append(self.store[back])
+
+        return str(nodes) 

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_last(element)
+        return None
 
     def pop(self):
         """ Removes an element from the top
@@ -21,18 +22,25 @@ def pop(self):
             The Stack is empty.
             returns None
         """
-        pass
+        try:
+            return self.store.remove_last()
+        except:
+            raise StackEmptyException
+
 
     def empty(self):
         """ Returns True if the Stack is empty
             And False otherwise
         """
-        pass
+        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.visit()