I need to understand and write a code using C$++.$BufferPool class is responsible for caching pages in memory that have been recently read from disk. All operators read and write pages from various files on disk through the buffer pool. It consists of a fixed number of pages, defined by the DEFAILT$\_$NUM$\_$PAGES constant. You will implement an eviction policy and the BufferPool::getPage$()$ method used by as well as some helper methods. You will be required to implement a LRU $($least recently used$)$ eviction policy to pass all the test cases.

The Database class provides a method, Database::getBufferPool$(),$ that returns a reference to the buffer pool.