How to use define constants when concatenating?

Question

C++ / C#

Let there be a code:
#define N n
#define DECODE(q,w,e,r) q ## w ## e ## r
#define START DECODE(m,a,i,N)
Then when concatenating we get START = maiN . I have two questions:
1) Why is the name of the constant N substituted, and not its value (n)?
2) Is it possible to use define constants when concatenating in a code section, as in the example above? To get START = main.
I work in VS 2013.
Please, if you do not answer the question directly, then at least poke your face into the necessary literature to read.
Thanks

Answer 1

I ask if you do not answer the question directly, then at least poke your face into the necessary literature to read.

www.open-std.org/JTC1/SC22/WG14
You can download the standard there and find the description
6.10.3 Macro replacement
And macros are used for simple replacements, when you need, for example, to insert a piece of code in several places, but it does not pull on a function. That is how they should be considered - as an automated insertion, no more.