From 6b9952c8a4d05ba4fb52c65e6726a6b0b336c171 Mon Sep 17 00:00:00 2001
From: Nourhan Alenany <alenany.n21@gmail.com>
Date: Sun, 17 Jul 2022 22:41:22 -0700
Subject: [PATCH] Add solution to stacks and queues

---
 stacks_queues/queue.py | 31 +++++++++++++++++++++++++------
 stacks_queues/stack.py | 19 ++++++++++++++-----
 2 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/stacks_queues/queue.py b/stacks_queues/queue.py
index d66dab2..208c900 100644
--- a/stacks_queues/queue.py
+++ b/stacks_queues/queue.py
@@ -23,34 +23,48 @@ def enqueue(self, element):
             In the store are occupied
             returns None
         """
-        pass
+        if self.size == INITIAL_QUEUE_SIZE:
+            raise QueueFullException()
+        index = self.rear % self.buffer_size
+        self.store[index] = element
+        self.rear -= 1
+        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()
+        index = self.front % self.buffer_size
+        element = self.store[index]
+        self.front -= 1
+        self.size -= 1
+        return element
 
     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
+        index = self.front % self.buffer_size
+        return self.store[index]
         
 
     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
+        return self.size == 0
 
     def __str__(self):
         """ Returns the Queue in String form like:
@@ -58,4 +72,9 @@ def __str__(self):
             Starting with the front of the Queue and
             ending with the rear of the Queue.
         """
-        pass
+        result = []
+        for index in range(self.front, self.front - self.size, -1):
+            result.append(self.store[index % self.buffer_size])
+        return str(result)
+
+
diff --git a/stacks_queues/stack.py b/stacks_queues/stack.py
index 94fb2a6..ec75756 100644
--- a/stacks_queues/stack.py
+++ b/stacks_queues/stack.py
@@ -12,22 +12,26 @@ def push(self, element):
         """ Adds an element to the top of the Stack.
             Returns None
         """
-        pass
+        self.store.add_last(element)
 
     def pop(self):
         """ Removes an element from the top
             Of the Stack
             Raises a StackEmptyException if
             The Stack is empty.
-            returns None
+            returns the removed element
         """
-        pass
+        if self.empty():
+            raise StackEmptyException()
+        
+        return self.store.remove_last()
+        
 
     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:
@@ -35,4 +39,9 @@ def __str__(self):
             Starting with the top of the Stack and
             ending with the bottom of the Stack.
         """
-        pass
+        values = []
+
+        current = self.store.get_last()
+        while current:
+            values.append(str(current.value))
+            current = current.prev
\ No newline at end of file