Introduction to the Turbo C Tutorial


             The programming language C, was originally developed by
        Dennis  Ritchie of Bell Laboratories and was designed to run
        on a PDP-11 with a UNIX operating system.   Although it  was
        originally  intended  to run under UNIX,  there has  been  a
        great  interest  in  running it under the  MS-DOS  operating
        system and specifically on the IBM PC and  compatibles.   It
        is an excellent language for this environment because of the
        simplicity of expression,  the compactness of the code,  and
        the wide range of applicability.

             It  is  not a good "beginning" language because  it  is
        somewhat cryptic in nature.  It allows the programmer a wide
        range of operations from high level down to a very low level
        approaching the level of assembly language.   There seems to
        be no limit to the flexibility available.  One experienced C
        programmer made the statement,  "You can program anything in
        C", and the statement is well supported by my own experience
        with  the  language.    Along  with  the  resulting  freedom
        however,  you take on a great deal of responsibility because
        it is very easy to write a program that destroys itself  due
        to  the  silly little errors that the Pascal  compiler  will
        flag  and call a fatal error.   In C,  you are very much  on
        your own as you will soon find.

             Since C is not a beginners language,  I will assume you
        are  not a beginning programmer,  and I will not attempt  to
        bore you by defining a constant and a variable.  You will be
        expected to know these basic concepts.   You will,  however,
        be  expected to know nothing of the C programming  language.
        I  will begin with the most basic concepts of C and take you
        up  to  the  highest level of C  programming  including  the
        usually intimidating concepts of pointers,  structures,  and
        dynamic allocation.   To fully understand these concepts, it
        will  take a good bit of time and work on your part  because
        they  not  particularly easy to grasp,  but  they  are  very
        powerful tools.   Enough said about that, you will see their
        power when we get there,  just don't allow yourself to worry
        about them yet.

             Programming  in C is a tremendous asset in those  areas
        where you may want to use Assembly Language but would rather
        keep it a "simple to write" and "easy to maintain"  program.
        It  has  been said that a program written in C  will  pay  a
        premium  of  a  50 to 100% increase in  runtime  because  no
        language  is  as  compact  or  fast  as  Assembly  Language.
        However, the time saved in coding can be tremendous,  making
        it the most desirable language for many programming  chores.
        In  addition, since most programs spend 90 percent of  their
        operating time in only 10 percent or less of the code, it is
        possible  to  write  a program in C, then  rewrite  a  small
        portion  of the code in Assembly Language and  approach  the


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                   Introduction to the Turbo C Tutorial


        execution  speed  of  the same program if  it  were  written
        entirely in Assembly Language.

             Even  though the C language enjoys a good  record  when
        programs are transported from one implementation to another,
        there  are differences in compilers as you will find anytime
        you  try to use another compiler.   Most of the  differences
        become apparent when you use nonstandard extensions such  as
        calls  to  the DOS BIOS,  but even these differences can  be
        minimized  by careful choice of programming means.  Turbo  C
        follows  the  developing  ANSI standard so  well  that  your
        programs  developed with Turbo C should be very portable  if
        you should decide to use a different ANSI standard compiler.

             Throughout this tutorial, every attempt will be made to
        indicate  to  you what constructs are available in  every  C
        compiler  because they are part of the accepted standard  of
        programming practice.  Most of those constructs will use the
        generic  name "C", such as in the statement, "writing  to  a
        file is easy in C after you master a few fundamentals."   If
        a  particular  construct  is  a  Borland  extension  to  the
        language, it will be pointed out as such as an indication to
        you that it may not be available on other compilers.

             Turbo  C  is a very capable compiler, but  due  to  the
        tremendous  versatility of this compiler, it could  be  very
        difficult  for you to learn how to use it  effectively.   If
        you are a complete novice to programming, you will  probably
        find the installation instructions somewhat confusing.   The
        file on the SOURCE disk named COMPILER.DOC is provided  just
        for  you  since it will take you step by  step  through  the
        installation procedure and even show you how to compile  and
        run  your  first program.  You should print out  a  copy  of
        COMPILER.DOC at this time and use it as an aid to installing
        Turbo C on your system.

             This  tutorial cannot cover all aspects of  programming
        in C, simply because there is too much to cover, but it will
        instruct  you  in  all you need for  the  majority  of  your
        programming  in C.  You will receive instruction in  all  of
        the  programming constructs in C, but what must  be  omitted
        are  methods of programming since these can only be  learned
        by  experience.   More importantly, it will  teach  you  the
        vocabulary  of C so that you can go on to the more  advanced
        techniques of using the programming language C.

             It  would definitely be to your advantage to study  the
        Turbo C User's Guide at this point to gain experience in how
        to  edit,  compile, and run a C program.   You  should  read
        chapter  2  to  familiarize  yourself  with  the  Integrated
        Environment and learn how to use it, and to learn how to use


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                   Introduction to the Turbo C Tutorial


        the  full  screen  editor which is a part  of  the  Turbo  C
        Integrated Environment.

             Remember  to read the file COMPILER.DOC To aid  you  in
        compiling your first program.
















































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