C++ Language/Preprocessing/Tokenization

When your C++ source file is being compiled, one of the first things that happens is your compiler uses its preprocessor to "tokenize" your program.

Tokenization would process code like iA+++iB by splitting it into four tokens (variable identifier iA, then operator ++, then operator +, then variable identifier iB).

A preprocessor macro is able to use ## within its definition, to construct a compilation-token while the macro expands.

Additional information about tokenization (includes interactive examples)