How is the room number compiled?

The numbering adopted by China has a principle, that is, it starts from the north, ends in the south, ends in the west and ends in the east. You can see this in the street. If it is divided into single and even numbers, it starts with 1, so the single number is in the north and the even number is in the south.

Then some odd and even numbers in the room and the odd and even numbers on the left can be used flexibly.

For example:

Building c c-101c-103c-105 .......

C is the building number, the first is the floor, and the second is the room number.