class MovingAverage:

    def __init__(self, size: int):
        """
        Initialize your data structure here.
        """
        self.size=size+1
        self.front=0
        self.rear=0
        self.queue=[None for _ in range(size+1)]
        self.sum=0

    def next(self, val: int) -> float:
        # 满了
        if (self.rear+1)%self.size==self.front:
            self.front=(self.front+1)%self.size
            self.sum-=self.queue[self.front]

            self.rear=(self.rear+1)%self.size
            self.queue[self.rear]=val
            self.sum+=val
            return 1.0*self.sum/(self.size-1)
        else:
            self.rear=self.rear+1
            self.queue[self.rear]=val
            self.sum+=val
            return 1.0*self.sum/(self.rear-self.front)



# Your MovingAverage object will be instantiated and called as such:
# obj = MovingAverage(size)
# param_1 = obj.next(val)