list_queue.py

class QueueFullError(Exception):
    pass


class QueueEmptyError(Exception):
    pass


class ListQueue():

    def __init__(self, size) -> None:
        self.items = []
        self.front = 0
        self.rear = 0 
        self.size = size

    
    def enqueue(self, data):
        if self.full:
            raise QueueFullError()
        
        self.items.append(data)
        self.rear += 1


    def dequeue(self):
        if self.empty:
            raise QueueEmptyError()
        
        data = self.items.pop(0)
        self.rear -= 1
        return data


    @property
    def full(self):
        return self.size == self.rear
    

    @property
    def empty(self):
        return self.rear == 0
    


queue = ListQueue(3)
queue.enqueue(10)
queue.enqueue(20)
queue.enqueue(30)

print(queue.dequeue())
print(queue.dequeue())
print(queue.dequeue())