Stacks-queues (Sumitra, Scissors class)

stacks_queues/queue.py

@@ -15,48 +15,98 @@ 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 == self.buffer_size:
+            raise QueueFullException("Queue if full")
+
+        # condition for empty queue
+        elif (self.front == -1):
+            self.front = 0
+            self.rear = 0
+            self.store[self.rear] = element
+            self.size +=1 
+
+        else:
+            # next position of rear
+            self.rear = (self.rear + 1) % self.buffer_size
+            self.store[self.rear] = element
+            self.size +=1
 
     def dequeue(self):
         """ Removes an element from the Queue
             Raises a QueueEmptyException if 
             The Queue is empty.
             returns None
         """
-        pass
+        if self.size == 0:
+            raise QueueEmptyException("Queue is empty")
+
+        data = self.store[self.front]
+        self.store[self.front] = None
+        self.size -= 1
+
+        if self.front == self.rear:
+            self.front = -1
+            self.rear = -1
+        elif self.front == self.buffer_size-1:
+            self.front = 0
+        else:
+            self.front +=1
+
+        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.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
+        if self.size == 0:
+            return True 
+        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
+        elements = []
+
+        if self.front == -1:
+            return str(elements)
+
+        elif self.rear >= self.front:
+            for element in range(self.front, self.rear+1):
+                elements.append(self.store[element])
+
+        else:
+            for element in range(self.front, self.buffer_size):
+                elements.append(self.store[element])
+
+            for element in range(0, self.rear+1):
+                elements.append(self.store[element])
+
+        return str(elements)
+
+

stacks_queues/stack.py

@@ -12,7 +12,9 @@ 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
@@ -21,18 +23,22 @@ def pop(self):
             The Stack is empty.
             returns None
         """
-        pass
+        if self.store.length() == 0:
+            raise StackEmptyException("The Stack is empty")
+        return self.store.remove_first()
 
     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.__str__()