Part of a program text included for the benefit of the reader and
ignored by the compiler. Each language has its own syntax for
comments, usually a form of bracketing, e.g.
{.....} in Pascal,
/*.....*/ in PL/I
Some languages, including Ada, prefer "end-of-line" comments,
which are introduced by a characteristic symbol and are
automatically terminated at the end of a line. Older languages such
as BASIC and FORTRAN restrict comments to be whole lines and do not
allow them to be appended to a line of code.
