BTC Source code amount.h file I have question about the source code, under src/amount.h I see the max coin supply being 21.000.000 (million) under the variable called MAX_MONEY. I want to ask what other variables mean, 

CAmount COIN

CAmount CENT

And I want to know how they're used. As an interest in forking coins, I am analyzing source code and I would like to see how these numbers affect the blockchain.

Here is the link.

https://github.com/bitcoin/bitcoin/blob/master/src/amount.h
I see the max coin supply being 21.000.000 (million) under the variable called MAX_MONEY.

MAX_MONEY is not what controls the maximum coin supply. It is just a variable for use elsewhere that estimates the coin supply. The actual coin supply is regulated by the halving interval and the starting generation amount.

CAmount COIN
CAmount CENT

The base unit in Bitcoin is actually a satoshi, which is 1/100000000th of a Bitcoin. So COIN and CENT are used as multiplier values to convert units in Bitcoin (for COIN) and bitcent (1/100th of a Bitcoin) (for CENT) to the actual value that would be found in transactions which is in satoshis.