
                Introduction to the TURBO Pascal Tutorial


             Assuming  you know nothing at all about Pascal, and  in
        fact,  that  you  may  know  nothing  about  programming  in
        general, we will begin to study Pascal.  If you are  already
        somewhat  familiar with programming and  especially  Pascal,
        you  will  probably want to skip very  quickly  through  the
        first few chapters.  You should at least skim the first  few
        chapters,  and  you  should  read  the  remainder  of   this
        introduction.

             A  few comments are in order to get us started  in  the
        right direction.  The sample programs included on the  disks
        are  designed to teach you the basics of Pascal and they  do
        not  include any clever or tricky code.  Nearly all  of  the
        programs  are  really  quite dumb as  far  as  being  useful
        programs,  but  all  will teach one or  more  principles  of
        Pascal.   I have seen one tutorial that included a  12  page
        program  as  the first example.  In fact there were  only  2
        example  programs  in  the  entire  tutorial,  and  it   was
        impossible to glean the essentials of programming from  that
        system.  For this reason, I will completely bypass any  long
        programs  until the very end of this tutorial. In  order  to
        illustrate fundamental concepts used in Pascal  programming,
        all  programs will be very short and concise until we  reach
        the last chapter.

             The  last  chapter has some rather  large  programs  to
        illustrate to you how to write a large program.  It would be
        a  disservice  to you to show you all of the  constructs  of
        Pascal  and  not  show you how to put  them  together  in  a
        meaningful  way to build a large program.  After  completing
        all of the fundamentals of Pascal, it will then be very easy
        for you to use the tools learned to build as large a program
        as you desire.

             Another  problem I have noticed in example programs  is
        the  use  of one word for all definitions.  For  example,  a
        sort program is stored in a file called SORT, the program is
        named Sort, and various parts of the program are referred to
        as Sort1, Sort2, etc.  This can be confusing since you  have
        no  idea  if  the  program name must  be  the  same  as  the
        filename, or if any of the other names were chosen to be the
        same  because of some obscure rule not  clearly  documented.
        For  this  reason,  the  example  programs  use   completely
        arbitrary  names whenever the choice of a name adds  nothing
        to  the  readability  or  clarity  of  a  program.   As   an
        illustration of this, the first program is named  Puppy_Dog.
        This  adds nothing to the understanding of the  program  but
        does  illustrate that the program name means nothing to  the
        Pascal compiler concerning what the program does.




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                Introduction to the TURBO Pascal Tutorial


             Due  to the fundamental design of the Pascal  language,
        certain words are "reserved" and can only be used for  their
        defined  purposes.   These are listed in your  TURBO  Pascal
        reference manual (page 37 - version 3.0; page 196 -  version
        4.0).   All  of  the sample programs in  this  tutorial  are
        written  with the reserved words in all lower-case  letters,
        and  the user variables in lower case with the first  letter
        capitalized  since  this is becoming the  accepted  industry
        standard.   Don't worry about what reserved words  are  yet,
        they will be completely defined later.

                            WHAT IS A COMPILER?

             There  are  two  primary methods used  in  running  any
        computer  program  that  is written in a  readable  form  of
        English.    The   first  method  is  an   interpreter.    An
        interpreter  is  a program that looks at each  line  of  the
        "English"  program, decides what the "English" on that  line
        means, and does what it says to do.  If one of the lines  is
        executed  repeatedly, it must be scanned and  analyzed  each
        time,  greatly slowing down the solution of the  problem  at
        hand.   A  compiler, on the other hand, is  a  program  that
        looks at each statement one time and converts it into a code
        that  the computer understands directly.  When the  compiled
        program  is  actually  run, the computer does  not  have  to
        figure  out  what each statement means, it is already  in  a
        form that the computer can run directly, hence a much faster
        execution of the program.

             This   tutorial  is  written  especially  for   Borland
        International's  TURBO  Pascal  compilers  version  3.0   or
        version 4.0.  These are very high quality compilers that can
        do nearly anything you will ask them to do since they are so
        flexible.  The original intent of this tutorial was to write
        it  in  such a way that it would be completely  generic  and
        usable  with any good Pascal compiler.  The  programmers  at
        Borland  included  a  great many nonstandard  aids  for  the
        Pascal language and resulted in a very good product that has
        dominated the market for microcomputers.  To completely omit
        all of the extensions would do those of you with the Borland
        compiler  a real disservice, and to include  the  extensions
        would not allow other compilers to be used effectively  with
        this tutorial.

             The  decision  was  made  to  stay  with  the   Borland
        extensions and make the tutorial very difficult to use  with
        other  compilers.   TURBO Pascal is so inexpensive  that  it
        would  be a wise decision to purchase a copy solely for  the
        purpose  of  learning the Pascal programming  language  then
        moving to a larger compiler on a minicomputer or a mainframe
        using  the accumulated knowledge to very quickly  learn  the


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                Introduction to the TURBO Pascal Tutorial


        extensions  provided  by that particular compiler.   At  any
        rate,  this tutorial will not teach you everything you  will
        ever need to know about Pascal.  It will, however, teach you
        the  fundamentals and the terminology needed to progress  on
        your own into more advanced topics of Pascal and programming
        in general.  You will find that experience will be your best
        teacher.

             Some of the example files will only work properly  with
        TURBO  Pascal version 3.0 and some will only  work  properly
        with  version 4.0, but most will work with either.  It  will
        be clearly indicated to you which files will work with  each
        of the two versions of TURBO Pascal.

                    WHAT ABOUT TURBO PASCAL VERSION 2.0?

             Most  of  the files will compile  properly  with  TURBO
        Pascal version 2.0, but no warning will be given since  that
        version has been superseded for so long.  It will pay you to
        purchase a newer version because of the flexibility.  If you
        choose not to however, this tutorial will work fine in  most
        cases  if  you  follow the  instructions  for  TURBO  Pascal
        version 3.0.

                   PREPARATION FOR USE OF THIS TUTORIAL.

             Copy the example files onto your TURBO working disk and
        you  are  ready to begin, provided of course that  you  have
        already  learned  how to start the TURBO system and  how  to
        edit  a Pascal file.  Be sure you make a backup copy of  the
        Pascal  tutorial disks so you cannot accidentally  lose  all
        information  on  the distribution disks.  If you  are  using
        TURBO  Pascal version 3.0, you should read Chapter 1 of  the
        reference  manual to be ready to use this tutorial,  and  if
        you  are  using TURBO Pascal version 4.0,  you  should  read
        parts of chapters 1, 2, & 11 of your reference manual.   You
        should  be  familiar with use of the  editor  supplied  with
        TURBO Pascal before beginning.

             If  you are not using TURBO Pascal, you will  still  be
        able  to  compile and execute many of  these  Pascal  files,
        since  most  of  the examples use  standard  Pascal  syntax.
        There will be some statements used which are unique to TURBO
        Pascal and will probably not work with your compiler.   This
        will  be  especially true when you come to  the  chapter  on
        standard input and output since this is where most compilers
        differ.   Unfortunately, this is one of the  most  important
        aspects of any programming language, since it is required to
        get data into and out of the computer to do anything useful.




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                Introduction to the TURBO Pascal Tutorial


             It  is  highly suggested that you  do  the  programming
        exercises  after  you complete the study for  each  chapter.
        They  are carefully selected to test your  understanding  of
        the material covered in that chapter.  If you do not  write,
        enter,  debug,  and  run these programs, you  will  only  be
        proficient  at  reading  Pascal.  If you  do  the  exercises
        completely,  you  will have a good start at being  a  Pascal
        program writer.

             It should also be mentioned that this tutorial will not
        teach  you  everything  you will ever  need  to  know  about
        Pascal.   You will continue to learn new techniques as  long
        as  you continue to write programs.  Experience is the  best
        teacher  here just as it is in any endeavor.  This  tutorial
        will teach you enough about Pascal that you should feel very
        comfortable  as you search through the reference manual  for
        some  topic.  You will also be able to read  and  understand
        any Pascal program you find in textbooks or magazines.

             When you are ready, I will meet you in Chapter 1.

































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