diff --git a/stacks_and_queues/circular_queue.py b/stacks_and_queues/circular_queue.py
new file mode 100644
index 0000000..a87fa47
--- /dev/null
+++ b/stacks_and_queues/circular_queue.py
@@ -0,0 +1,115 @@
+## implement a circular queue
+
+
+class CircularQueue:
+
+    def __init__(self, k: int):
+        self.head = 0
+        self.tail = 0
+        self.size = k
+        self.queue = [None] * self.size
+        
+    def enQueue(self, value: int) -> bool:
+
+        if value is None:
+            return False
+            
+        if self.isFull():
+            return False
+
+        if self.isEmpty():
+            self.heard = 0
+        
+        while self.queue[self.tail] != None:
+            self.tail += 1 
+            if self.tail == self.size:
+                self.tail = 0
+    
+        self.queue[self.tail] = value
+        return True
+
+    def deQueue(self) -> bool:
+
+        if self.isEmpty():
+            return False
+
+        value = self.queue[self.head]
+        self.queue[self.head] = None
+        self.head += 1
+
+        if self.head == self.size:
+            self.head = 0
+
+        return True
+
+    def Front(self) -> int:
+        return self.queue[self.head] or -1
+        
+    def Rear(self) -> int:
+        return self.queue[self.tail] or -1
+        
+    def isEmpty(self) -> bool:
+        for n in self.queue:
+            if n is not None:
+                return False
+        return True
+
+    def isFull(self) -> bool:
+        for n in self.queue:
+            if n is None:
+                return False
+        return True
+        
+
+if __name__ == "__main__":
+
+    q = CircularQueue(5)
+    print(f'q: {q.queue}')
+    print(f'q.isEmpty(): {q.isEmpty()}')
+    print(f'q.isFull(): {q.isFull()}')
+    print(f'q.enQueue(1): {q.enQueue(1)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.enQueue(2): {q.enQueue(2)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.enQueue(3): {q.enQueue(3)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.enQueue(4): {q.enQueue(4)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'isFull(): {q.isFull()}')
+    print(f'q.enQueue(5): {q.enQueue(5)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'isFull(): {q.isFull()}')
+    print(f'q.isEmpty(): {q.isEmpty()}')
+    print(f'q: {q.queue}')
+    print(f'q.enQueue(6): {q.enQueue(6)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'isFull(): {q.isFull()}')
+    print(f'q.isEmpty(): {q.isEmpty()}')
+    print()
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.Front(): {q.Front()}')
+    print(f'q.isEmpty(): {q.isEmpty()}')
+    print(f'q.isFull(): {q.isFull()}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.Front(): {q.Front()}')
+    print(f'q.isEmpty(): {q.isEmpty()}')
+    print(f'q.isFull(): {q.isFull()}')
diff --git a/stacks_and_queues/circular_queue_II.py b/stacks_and_queues/circular_queue_II.py
new file mode 100644
index 0000000..af29665
--- /dev/null
+++ b/stacks_and_queues/circular_queue_II.py
@@ -0,0 +1,107 @@
+## implement a circular queue
+
+
+class CircularQueue:
+
+    def __init__(self, k: int):
+        self.head = -1
+        self.tail = -1
+        self.size = k
+        self.queue = [None] * self.size
+        
+    def enQueue(self, value: int) -> bool:
+
+        if self.isFull():
+            return False
+
+        if self.isEmpty():
+            head = 0;
+
+        self.tail = (self.tail + 1) % self.size
+        self.queue[self.tail] = value
+
+        return True
+
+    def deQueue(self) -> bool:
+
+        if self.isEmpty():
+            return False
+
+        if self.head == self.tail:
+            self.head = -1
+            self.tail = -1
+            return True
+        
+        self.head = (self.head + 1) % self.size
+
+        return True
+
+    def Front(self) -> int:
+        if self.isEmpty():
+            return -1
+        return self.queue[self.head]
+        
+    def Rear(self) -> int:
+        if self.isEmpty():
+            return -1
+        return self.queue[self.tail]
+        
+    def isEmpty(self) -> bool:
+        return self.head == -1
+
+    def isFull(self) -> bool:
+        return (self.tail + 1) % self.size == self.head
+        
+
+if __name__ == "__main__":
+
+    q = CircularQueue(5)
+    print(f'q: {q.queue}')
+    print(f'q.isEmpty(): {q.isEmpty()}')
+    print(f'q.isFull(): {q.isFull()}')
+    print(f'q.enQueue(1): {q.enQueue(1)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.enQueue(2): {q.enQueue(2)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.enQueue(3): {q.enQueue(3)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.enQueue(4): {q.enQueue(4)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'isFull(): {q.isFull()}')
+    print(f'q.enQueue(5): {q.enQueue(5)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'isFull(): {q.isFull()}')
+    print(f'q.isEmpty(): {q.isEmpty()}')
+    print(f'q: {q.queue}')
+    print(f'q.enQueue(6): {q.enQueue(6)}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'isFull(): {q.isFull()}')
+    print(f'q.isEmpty(): {q.isEmpty()}')
+    print()
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.Front(): {q.Front()}')
+    print(f'q.isEmpty(): {q.isEmpty()}')
+    print(f'q.isFull(): {q.isFull()}')
+    print(f'q.deQueue(): {q.deQueue()}')
+    print(f'q: {q.queue}')
+    print(f'h: {q.head}, t: {q.tail}')
+    print(f'q.Front(): {q.Front()}')
+    print(f'q.isEmpty(): {q.isEmpty()}')
+    print(f'q.isFull(): {q.isFull()}')
diff --git a/stacks_and_queues/moving_average.py b/stacks_and_queues/moving_average.py
new file mode 100644
index 0000000..5733348
--- /dev/null
+++ b/stacks_and_queues/moving_average.py
@@ -0,0 +1,25 @@
+'''
+Given a stream of integers and a window size, calculate the moving average of all integers in the sliding window.
+
+Implement the MovingAverage class:
+
+MovingAverage(int size) Initializes the object with the size of the window size.
+double next(int val) Returns the moving average of the last size values of the stream.
+'''
+
+class MovingAverage:
+
+    def __init__(self, size: int):
+        self.queue = []
+        self.size = size
+        
+
+    def next(self, val: int) -> float:
+        
+        self.queue.append(val)
+        
+        if len(self.queue) > self.size:
+            self.queue.pop(0)
+        
+        return sum(self.queue) / len(self.queue)
+