Algorithms 2

Algorithms meant to be performed by humans can be expressed in any way that
the humans can understand.  Algorithms meant to be performed by computers
must be expressed in a language computers can interpret.  Most computers
are designed to interpret algorithms written in a very crude notation
("machine language") that most humans find unsatisfactory as a language in
which to express algorithms.  We meet the needs of both the human algorith
designer and the computer interpreting the algorithm by providing a
translation;  programmers write algorithms in a language designed for
convenience and expressiveness, the algorithm is translated (by another,
pre-existing computer program) into machine language, and the machine
language version of the algorithm is carried out by the computer.  The
programmer need not know anyghing about the machine language, little
programming is done in machine language.

Pascal is a language for writing algorithms, using a misture of English and
mathematical notation.  Programs written in Pascal can be translated, by
other programs called ←compilers← or ←translators←, into the machine
languages of most popular computers.  Because Pascal is a standard,
programs written in Pascal can be shared among the users of diverse
computers, and can continue to be used without change when obsolete
computers are replaced by newer ones.

Most Pascal translators accept programs in Pascal extended by notations to
make more efficient use of facilites peculiar to a particular computer.
Some translators actually accept programs written in dialects of Pascal.
The International Standards Organization (ISO) has formulated a definition
of Pascal, called Standard Pascal, which is widely accepted; normally,
programs in Standard Pascal can be expected to work with all translators of
recent design.  This text uses Standard Pascal almost almost exclusively;
departures to use computer capabilities not expressible in Pascal are
explicitly labeled non-standard.