FILE 0-object_like_macro.h is a header file that defines a macro named size and an abbreviation for the token 1024.
FILE 1-pi.h is a header file that defines a macro named PI and an abbreviation for the token 3.14159265359.
FILE 2-main.c is a program that prints the name of the file it was complied from.
FILE 3-function_like_macro.h is a function-like macro ABS(x) that computes the absolute value of a number x.
FILE 4-sum.h is a function-like macro SUM(x, y) that computes the sum of the numbers x and y.