2. CPP macroexpander

C++ shares with the C programming language a "macroexpansion" phase, i.e. a C++ program is not evaluated or compiled as is; it first undergoes a rewrite that is controlled by the user, by means of a macroexpander called CPP (C pre-processor). The language used to manipulate CPP is fairly rudimentary. It can only be used to perform simple transformations and, by way of calculation, only allows the concatenation of identifiers and the construction of character strings. Despite this simplicity, CPP plays an absolutely central role in both C and C++ development. In particular, since CPP enables conditional compilation, it is generally used to implement those parts of a program that are intrinsically non-portable (for example, parts that depend on the specifics of a particular operating system or hardware). CPP features include

• inclusion of source...