What do preprocessing and macros in c++ mean, and what are their effects in programming

A C preprocessor is a special compiler for processing text files that can add, modify, and delete specific text in the source code. Macros are special instructions used during compilation to define an identifier and then use it to represent a string or a more complex program structure. In programming, the effect of C preprocessor and macros is to improve the efficiency of programming and the maintainability of code.