The first line in VOLUME.C is a comment:
/* VOLUME.C: Calculate sphere's volume. */
Summary: Comments make a program more readable.
In C, a comment begins with a slash-asterisk (/*) and ends with an asterisk-slash (*/ ). Because C is a compact language with very few keywords, comments play an important role in making your programs readable.
You can't nest comments (put one comment inside another). The following line creates a syntax error:
/* Error! /* You can't */ nest comments in C. */