C++ Programming/Programming Languages/C++

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[edit] Introducing C++

C++ (pronounced "see plus plus") is a general-purpose, object-oriented, statically typed, free-form, multi-paradigm programming language supporting procedural programming, data abstraction, and generic programming. During the 1990s, C++ became one of the most popular computer programming languages.

[edit] History

Bjarne Stroustrup a Computer Scientist, from Bell Labs was the designer and original implementer of C++ (originally named "C with Classes") during the 1980s as an enhancement to the C programming language. Enhancements started with the addition of classes, followed by, among many features, virtual functions, operator overloading, multiple inheritance, templates, and exception handling, these and other features are covered in detail along this book.

The C++ programming language is a standard recognized by the ANSI (The American National Standards Institute), BSI (The British Standards Institute), DIN (The German national standards organization), several other national standards bodies, and was ratified in 1998 by the ISO (The International Standards Organization) as ISO/IEC 14882:1998, consists of two parts: the Core Language and the Standard Library; the latter includes the Standard Template Library and the Standard C Library (ANSI C 89).

Features introduced in C++ include declarations as statements, function-like casts, new/delete, bool, reference types, const, inline functions, default arguments, function overloading, namespaces, classes (including all class-related features such as inheritance, member functions, virtual functions, abstract classes, and constructors), operator overloading, templates, the :: operator, exception handling, run-time type identification, and more type checking in several cases. Comments starting with two slashes ("//") were originally part of BCPL, and was reintroduced in C++. Several features of C++ were later adopted by C, including const, inline, declarations in for loops, and C++-style comments (using the // symbol).

The current version, which is the 2003 version, ISO/IEC 14882:2003 redefines the standard language as a single item. The STL that pre-dated the standardization of C++, and was originally implemented in Ada is now an integral part of the standard and requirement for a compliant implementation of the same. Many other C++ libraries exist which are not part of the Standard, such as Boost. Also, non-Standard libraries written in C can generally be used by C++ programs.

Since 2004, the standards committee (includes Bjarne Stroustrup) has been busy working out the details of a new revision of the standard, that has been temporarily titled C++0x, due publication in the end of 2011. Some implementations already support some of the proposed alterations.

C++ source code example

// 'Hello World!' program 
 
#include <iostream>
 
int main()
{
  std::cout << "Hello World!" << std::endl;
  return 0;
}

Traditionally the first program people write in a new language is called "Hello World." because all it does is print the words Hello World. Hello World Explained offers a detailed explanation of this code; the included source code is to give you an idea of a simple C++ program.

[edit] Overview

Before you begin your journey to understand how to write programs using C++, it is important to understand a few key concepts that you may encounter. These concepts are not unique to C++, but are helpful to understanding computer programming in general. Readers who have experience in another programming language may wish to skim through or skip this section entirely.

There are many different kinds of programs in use today. From the operating system you use that makes sure everything works as it should, to the video games and music applications you use for fun, programs can fulfill many different purposes. What all programs (also called software or applications) have in common is that they all are made up of a sequence of instructions written in some form of programming language. These instructions tell a computer what to do, and generally how to do it. Programs can contain anything from instructions to solve math problems or send emails, to how to behave when a video game character is shot in a game. The computer will follow the instructions of a program one instruction at a time from start to finish.

[edit] Why learn C++?

Why not? This is the most clarifying approach to the decision to learn anything. Although learning is always good, selecting what you learn is more important as it is how you will prioritize tasks. Another side of this problem is that you will be investing some time in getting a new skill set. You must decide how will this benefit you. Check your objectives and compare similar projects or see what the programming market is in need of. In any case, the more programming languages you know, the better.

If you are approaching the learning process only to add another notch under your belt, that is, willing only to dedicate enough effort to understand its major quirks and learn something about its dark corners then you should be best served in learning first two other languages, this will clarify what makes C++ special in its approach to programming problems. You should select one imperative language, and in this C will probably have a better market value and will have a direct relation to C++ (a good substitute would be ASM) and the second language should be an Object Oriented language like Java for the same reasons, as there is a close relation between the three languages.

If you are willing to dedicate a more than passing interest in C++ then you can even learn C++ as your first language, but dedicate some time understanding the different paradigms and why C++ is a multi-paradigm language, or how some like to call it, a hybrid language.

Learning C is not a requirement for understanding C++, but knowing how to use an imperative language is, C++ will not make it easy for you to understand and distinguish some of this deeper concepts, since that in C++ you are free to implement solutions with a greater range of freedom. Understanding what options to make will become the cornerstone of mastering the language.

You should not learn C++ if you are only interested in applying or learning about Object Oriented Programing since the nomenclature used and some of the approaches C++ takes to the problem will probably increase the difficulty level in learning and mastering those concepts, if you are truly interested in Object Oriented programming, the best language for that is Smalltalk.

As with all languages C++ has a specific scope of application, where it can truly shine, and if we take a quick comparison with the previous mentioned languages, C++ is harder to learn than C and Java but more powerful than both. C++ enables you to abstract from the little things you have to deal with in C or other lower level languages but will grant you a bigger control and responsibility than Java, but it will not provide the default features you can obtain in similar higher level languages. You will have to search and examine several external implementations of these features and freely select those that best serve your purposes or you may even have to implement your own solution.

[edit] Where to get a compiler

When you select your compiler you must take in consideration your system OS, your personal preferences and the documentation that you can get on using it.

One of most actualized and compatible compilers is GCC. The next section will show how to get a copy and install it on Windows. You can easily find information on the GCC website on how to do it under another OS. GCC is a decent choice, and can be obtained for free. Many Open Source platforms include a recent GCC version. Version 4.0 or later gives fairly good conformance to the C++ standard. Various IDEs are available to support GCC. For Windows, Microsoft Visual Studio Express is currently available free of charge (but not free as in non-proprietary) with a C++ compiler that can be used from the command line or from the supplied IDE. An IDE, or Integrated Development Environment, is generally a graphical environment which integrates functionality like editing, compiling, linking, and usually a help system etc.).

[edit] GCC

The GNU Compiler Collection is a free set of compilers developed by the Free Software Foundation, with Richard Stallman as one of the main architects.

There are many different pre-compiled GCC binaries on the Internet, some popular choices are listed below (with detailed steps for installation).

[edit] On Windows

Cygwin:

1. Go to http://www.cygwin.com and click on the "Install Cygwin Now" button in the upper right corner of the page.
2. Click "run" in the window that pops up, and click "next" several times, accepting all the default settings.
3. Choose any of the Download sites ("ftp.easynet.be", etc.) when that window comes up; press "next" and the Cygwin installer should start downloading.
4. When the "Select Packages" window appears, scroll down to the heading "Devel" and click on the "+" by it. In the list of packages that now displays, scroll down and find the "gcc-c++" package; this is the compiler. Click once on the word "Skip", and it should change to some number like "3.4" etc. (the version number), and an "X" will appear next to "gcc-core" and several other required packages that will now be downloaded.
5. Click "next" and the compiler as well as the Cygwin tools should start downloading; this could take a while. While you're waiting, go to http://www.crimsoneditor.com and download that free programmer's editor; it's powerful yet easy to use for beginners.
6. Once the Cygwin downloads are finished and you have clicked "next", etc. to finish the installation, double-click the Cygwin icon on your desktop to begin the Cygwin "command prompt". Your home directory will automatically be set up in the Cygwin folder, which now should be at "C:\cygwin" (the Cygwin folder is in some ways like a small Unix/Linux computer on your Windows machine -- not technically of course, but it may be helpful to think of it that way).
7. Type "g++" at the Cygwin prompt and press "enter"; if "g++: no input files" or something like it appears you have succeeded and now have the gcc C++ compiler on your computer (and congratulations -- you have also just received your first error message!).

MinGW + DevCpp-IDE

1. Go to http://www.bloodshed.net/devcpp.html, choose the version you want (eventually scrolling down), click on the appropriate download link! For the most current version, you will be redirected to http://www.bloodshed.net/dev/devcpp.html
2. Scroll down to read the license and then to the download links. Download a version with Mingw/GCC. It's much easier than to do this assembling yourself. With a very short delay (only some days) you will always get the most current version of mingw packaged with the devcpp IDE. It's absolutely the same as with manual download of the required modules.
3. You get an executable that can be executed at user level under any WinNT version. If you want it to be setup for all users, however, you need admin rights. It will install devcpp and mingw in folders of your wish.
4. Start the IDE and experience your first project!
   You will find something mostly similar to MSVC, including menu and button placement. Of course, many things are somewhat different if you were familiar with the former, but it's as simple as a handfull of clicks to let your first program run.

[edit] For DOS

DJGPP:

• Go to Delorie Software and download the GNU C++ compiler and other necessary tools. The site provides a Zip Picker in order to help identify which files you need, which is available from the main page.
• Use unzip32 or other extraction utility to place files into the directory of your choice (ie. C:\DJGPP).
• Set the envionment variables to configure DJGPP for compilation, by either adding lines to autoexec.bat or a custom batch file:

  set PATH=C:\DJGPP\BIN;%PATH%

  set DJGPP=C:\DJGPP\DJGPP.ENV

• If you are running MS-DOS or Windows 3.1, you need to add a few lines to config.sys if they are not already present:

  shell=c:\dos\command.com c:\dos /e:2048 /p

  files=40

  fcbs=40,0

Note: The GNU C++ compiler under DJGPP is named gpp.

[edit] For Linux

• For Redhat, get a gcc-c++ RPM, e.g. using Rpmfind and then install (as root) using rpm -ivh gcc-c++-version-release.arch.rpm
• For Fedora Core, install the GCC C++ compiler (as root) by using yum install gcc-c++
• For Mandrake, install the GCC C++ compiler (as root) by using urpmi gcc-c++
• For Debian, install the GCC C++ compiler (as root) by using apt-get install g++
• For Ubuntu, install the GCC C++ compiler by using sudo apt-get install g++
• If you cannot become root, get the tarball from ftp://ftp.gnu.org/ and follow the instructions in it to compile and install in your home directory.

[edit] For Mac OS X

Xcode has GCC C++ compiler bundled. It can be invoked from the Terminal in the same way as Linux, but can also be compiled in one of XCode's projects.