


                                                     Introduction
                                                      WHAT IS C++

THE ORIGIN OF C++
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The C programming language was developed at AT&T for the purpose 
of writing the operating system for the PDP-11 series of 
computers which ultimately became the unix operating system.  
C was developed with the primary goal of operating efficiency.  
Bjarne Stroustrup, also of AT&T, developed C++ in order to add 
object oriented constructs to the C language.  Because object 
oriented technology was new at the time and all existing 
implementations of object oriented languages were very slow and 
inefficient, the primary goal of C++ was to maintain the 
efficiency of C.

C++ can be viewed as a traditional procedural language with some 
additional constructs.  Beginning with C, some constructs are 
added for object oriented programming and some for improved 
procedural syntax.  A well written C++ program will reflect 
elements of both object oriented programming style and classic 
procedural programming.  C++ is actually an extendible language 
since we can define new types in such a way that they act just 
like the predefined types which are part of the standard 
language.  C++ is designed for large scale software development.


HOW TO GET STARTED IN C++
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The C programming language was originally defined by the classic 
text authored by Kernigan and Ritchie, "The C Programming 
language", and was the standard used by all C programmers until a 
few years ago.  The ANSI standard for C was finally approved in 
December of 1989 and has become the official standard for 
programming in C.  The ANSI standard adds many things to the 
language which were not a part of the Kernigan and Ritchie 
definition, and changes a few.  The two definitions are not 
absolutely compatible and some experienced C programmers may not 
have studied the newer constructs added to the language by the 
ANSI-C standard.

This tutorial will assume a thorough knowledge of the C 
programming language and little time will be spent on the 
fundamental aspects of the language.  However, as a aid to those 
programmers that have learned the dialect of C as defined by 
Kernigan & Ritchie, some sections will be devoted to explaining 
the newer additions included in the ANSI-C standard.  As the 
ANSI-C standard was in development, many of the newer constructs 
from C++ were included as parts of C itself, so even though C++ 
is a derivation and extension of C, it would be fair to say that 
ANSI-C has some of its roots in C++.  An example is prototyping 
which was developed for C++ and later added to C.

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                                       Introduction - What is C++

The best way to learn C++ is by using it.  Almost any valid C 
program is also a valid C++ program and, in fact, the addition 
of about 12 keywords is the only reason that some C programs will 
not compile and execute as a C++ program.  There are a few other 
subtle differences, but we will save the discussion of them until 
later.  Since this is true, the best way to learn C++ is to 
simply add to your present knowledge and use a few new constructs 
as you need them for each new project.  It would be a tremendous 
mistake to try to use all of the new constructs in your first C++ 
program.  You would probably end up with an incomprehensive 
mixture of code that would be more inefficient than the same 
program written purely in C.  It would be far better to add a few 
new constructs to your toolkit occasionally, and use them as 
needed while you gain experience with their use.

As an illustration of the portability of C to C++, all of the 
example programs included in the Coronado Enterprises C tutorial 
compile and execute correctly when compiled as C++ programs with 
no changes.  None of the C++ programs will compile and execute 
correctly with any C compiler however, if for no other reason 
than the use of the new style of C++ comments.


HOW TO USE THIS TUTORIAL
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This tutorial is best used while sitting in front of your 
computer.  It is designed to help you gain experience with your 
own C++ compiler in addition to teaching you the proper use of 
C++.  Display an example program on the monitor, using whatever 
text editor you usually use, and read the accompanying text 
which will describe each new construct introduced in the example 
program.  After you study the program, and understand the new 
constructs, compile and execute the program with your C++ 
compiler.

After you successfully compile and execute the example program, 
introduce a few errors into the program to see what kind of error 
messages are issued.  If you have done much programming, you will 
not be surprised if your compiler gives you an error message that 
seems to have nothing to do with the error introduced.  This is 
because error message analysis is a very difficult problem with 
any modern programming language.  The most important result of 
these error introduction exercises is the experience you will 
gain using your compiler and understanding its nuances.  You 
should then attempt to extend the program using the techniques 
introduced with the program to gain experience.

The way this tutorial is written, you will not find it necessary 
to compile and execute every program.  At the end of each 
example program, listed in comments, you will find the result of 
execution of that program.  Some of the constructs are simple 
and easy for you to understand, so you may choose to ignore 
compilation and execution of that example program, depending 

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                                       Introduction - What is C++

upon the result of execution to give you the output.  Some 
students have used these results of execution to study several 
chapters of this tutorial on an airplane by referring to a 
hardcopy of the example programs.

In the text of this tutorial, keywords, variable names, and 
function names will be written in bold type as an aid when you 
are studying the example programs.


DIFFERENT C++ IMPLEMENTATIONS
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There are primarily two standards for naming C++ files, one using 
the extension CPP and the other using the extension CXX.  All 
files in this tutorial use the CPP extension for naming files.  
If your compiler requires the CXX extension it will be up to you 
to rename the files.  When C++ was in its infancy, header files 
generally used the extension .HPP, but there is a definite trend 
to use .H for all header files.  For that reason all header files 
in this tutorial will use that convention.

Even though we have tried to use the most generic form of all 
constructs, it is possible that some constructs will not actually 
compile and run with some C++ compilers.  As we find new 
implementations of C++, and acquire copies of them, we will 
compile and execute all files in an attempt to make all example 
programs as universal as possible.

The C++ language is very new and is changing rapidly.  The 
developer of the language, AT&T, has changed the formal 
definition several times in the last few years and the compiler 
writers are staying busy trying to keep up with them.  It would 
be best for you to search the more popular programming magazines 
for evaluations and comparisons of compilers.  New C++ 
implementations are being introduced at such a rapid rate, that 
we cannot make a compiler recommendation here.

A committee is currently meeting to produce an ANSI-C++ standard, 
but the standard is not expected to be available for general use 
until sometime in 1996.  Until then we must expect a few changes 
to the language.


PRINTING THE EXAMPLE PROGRAMS
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Some students prefer to work from a hardcopy of the example 
programs.  If you desire to print out the example programs, there 
is a batch file on the distribution disk to help you do this.  
Make the distribution disk the default drive and type PRINTALL at 
the user prompt.  The system will print out about 140 pages of 
C++ programs, all of the example programs in this tutorial.



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                                       Introduction - What is C++

The PRINTALL batch file calls the program named LIST.EXE once 
for each example program on the distribution disk.


PROGRAMMING EXERCISES
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There are programming exercises given at the end of each chapter 
to enable you to try a few of the constructs given in the 
chapter.  These are for your benefit and you will benefit greatly 
if you attempt to solve each programming problem.  If you merely 
read this entire tutorial, you will have a good working knowledge 
of C++, but you will only become a C++ programmer if you write 
C++ programs.  The programming exercises are given as suggestions 
to get you started programming.

An answer for each programming exercise is given in the ANSWERS 
directory on the distribution disk.  The answers are all given 
in compilable C++ source files named in the format CHnn_m.CPP, 
where nn is the chapter number and m is the exercise number.  If 
more than one answer is required, an A, B, or C, is included 
following the exercise number.


RECOMMENDED ADDITIONAL READING
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Brad Cox.  "Object Oriented Programming, An Evolutionary 
     Approach".  Addison-Wesley, 1986.  This book is excellent 
     for a study of object oriented programming and what it is, 
     but since it is based on Objective-C, it covers nothing of 
     the C++ language or how to use it.

Margaret Ellis & Bjarne Stroustrup. "The Annotated C++ Reference 
     Manual".  Addison-Wesley, 1990.  This is the base document 
     for the ANSI-C++ standard.  Even though it is the definitive 
     book on C++, it would be difficult for a beginner to learn 
     the language from this book alone.

Scott Meyers.  "Effective C++, 50 Specific Ways to Improve Your 
     Programs and Designs".  Addison-Wesley, 1992.  This book 
     is excellent for the advanced C++ programmer, but it is 
     definitely not for the beginner.

Note that the C++ culture is in rapid change and by the time you 
read this, there will be additional well written texts available 
as aids to your learning the syntax and proper use of the C++ 
programming language.







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