C16 - Spruce - Vange Spracklin

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

@@ -15,47 +15,78 @@ 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.front == -1:
+            self.front = 0
+            self.rear = 0
+        elif self.size == self.buffer_size:
+            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('The queue is empty')
+        else:
+            return_value = self.store[self.front]
+            self.store[self.front] = None
+            self.front = (self.front + 1) % self.buffer_size
+            self.size -= 1
+            return return_value
 
     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:
+            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
+        else:
+            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
+        strang = ""
+        count = 0
+        next = self.front
+        while count < self.size:
+            strang = strang + str(self.store[next]) 
+            if count != self.size - 1:
+                strang = strang + ", "
+            count += 1
+            next = (next + 1) % self.buffer_size
+        return "[" + strang + "]"

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 +22,30 @@ def pop(self):
             The Stack is empty.
             returns None
         """
-        pass
+        if self.store.head == None:
+            return None
+        return self.store.remove_last()
+        # return None
 
     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
+        if self.empty:
+            return "[]"
+        else:
+            values = []
+            current = self.store.head
+            while current.next:
+                values.append(str(current.value))
+                current = current.next
+            da_string = ", ".join(values)
+            return "[" + da_string  + "]"