Given a stream of integers and a window size, calculate the moving average of all integers in the sliding window. Implement a class called MovingAverage that has the following methods:

• Constructor (int size): This constructor initializes the object with the specified window size.

• double next (int val): This method takes an integer value as input and returns the moving average of the last size values from the stream.

Constraints:

• $1 \leq$ size $\leq 100$

• $-10^3 \leq$ val $\leq 10^3$

• At most $10^2$ calls can be made to next.