An Overview of C++ - Practical C++ Programming

Goals of C++

Developed by Bjarne Stroustrup at AT&T Bell Labs in the early 1980s.
An ANSI/ISO committee is working on C++ standardization.
Influences: C, Simula 67, Algol 68
First version in 1980: “C with Classes”
- Classes: An Abstract Data Type Facility for the C Language, ACM SIGPLAN Notices, 1982
- Adding Classes to C: An Exercise in Language Evolution, Software — Practice and Experience, 1983
Renamed C++ in 1983/84
Educational Release in 1983
General Releases 1985, 1986, 1987, 1988, 1989, 1990, …
ANSI/ISO C++ Standard finalized in 1998.

The C++ Programming Language, (First Edition) Bjarne Stroustrup, Addison-Wesley, 1986 (was the ‘C++ Bible’, but is now completely out of date)
USENIX C++ Workshops in Sante Fe, New Mexico (1987) and Denver, Colorado (1988) (Proceedings available from USENIX Association)
The Annotated C++ Reference Manual (ARM), Margaret Ellis and Bjarne Stroustrup, Addison-Wesley, 1990 (The new ‘C++ Bible’ reference, and the base for the ANSI/ISO C++ standards effort)
The C++ Programming Language, (Third Edition) Bjarne Stroustrup, Addison-Wesley, 1997. This is really the new ‘C++ Bible’, and is a major rewrite of the Second Edition (which in turn considerably augmented the First Edition).
The Design and Evolution of C++, Bjarne Stroustrup, Addison-Wesley, 1994.
Some interesting insights into why the language is the way it is.
There are now lots of books on C++, some good, some bad, some terrible…

Probably the fastest-growing computer language (until Java came along).
Installed on thousands of computers from micro to mainframe, across the entire world.
Use of C++ has burgeoned
(Stroustrup estimated at one point that, over a considerable period of time, the number of C++ users was doubling every 4 to 6 months!)
Used in wide variety of applications:
- C++ compiler, debugger
- Financial Trading systems
- Switching systems
- Simulations
- Graphics/Windows
- etc., etc.

Roots same as those of C (Bell Labs)
- Similar ‘pragmatic’ approach (as opposed to ‘theoretical’)
Decidedly a hybrid Object-Oriented language
Supports Object-Oriented programming, but does not require it
Does not penalize you (in terms of performance) if you don’t use a feature.
C++ is a very large, complex language (at least as much as Ada).
Some people, especially from the ‘pure O-O’ camp, criticize it for its complexity and ‘warts’.
- There was a lot of ‘C++ bashing’ at the 1990 OOPSLA conference.
Bell Labs was reputed to use C++ as a ‘better lint’
C++ use has been growing by leaps and bounds, although not all its adherents use it for O-O.
At one point, it probably had no significant competition for being the predominant O-O programming language. This has changed with the advent of Java.

AT&T translator (cfront):
- A “front end” for a C compiler.
- Written by Stroustrup and others at Bell Labs.
- Generates C source code, not object code directly (this was key to C++’s initial wide acceptance and rapid growth)
- Written in C++ with a bootstrap version in C
True compilers:
- Microsoft Visual C++
- Borland C++Builder
- gcc (GNU C++ from the Free Software Foundation) for a wide variety of platforms.
- Sun C++ for Sun
- Lots of others, many from hardware vendors (HP, IBM, etc.)…

Note: The above list needs to be updated…

C++ is more than just ‘an enhanced C’
Features can be classified as:
- Small Enhancements
- Large Enhancements
Distinctions between ‘small’ and ‘large’ not always clear-cut.
All of the ‘Small Enhancements’ and some of the ‘Large Enhancements’ can be used without touching Object-Oriented programming.
To make optimal use of C++, however, it really pays to try to use a different ‘O-O mindset’.

Small Enhancements
- Line-style comments
- struct/union/enum tags become true type names
- Declaration placement
- Scope operator
- const specifier (stricter than ANSI C)
- Anonymous union
- Explicit (function-like) type conversion
- Function prototypes (stricter than ANSI C)
- Overloading of function names
- Default values for function parameters
- Functions with unspecified number of parameters (stricter than ANSI C)
- Reference parameters in functions
- inline specifier
- new and delete operators
- Pointers to void and functions returning void (stricter than ANSI C)

Large Enhancements
- Stronger typing, with the necessary extensions for object-oriented programming
- The class construct, and class member encapsulation
- Constructors and destructors (automatically invoked; guaranteed to be invoked on creation and destruction of an object)
- Overloading of operators and functions
- References (general use)
- friends of a class
- Member class objects
- const member functions
- static members
- Derived classes (including multiple derivation)
- virtual functions
- Virtual base classes
- Exceptions
- Templates

It has been said by a large organization using C++ that there are five levels a typical C user may go through when learning C++:
- Level 0: can be described as typical C and usually takes days to learn.
- Level 1: can be described as better C (C++’s stronger type checking) and usually takes a week or so to learn.
- Level 2: can be described as advanced C (inlining) and usually takes a month to learn.
- Level 3: can be described as abstract data type (defining classes) and usually takes up to six months to learn.
- Level 4: can be described as object-oriented programming paradign (use of inheritance and polymorphism) and usually takes up to a year to learn. This is also called an object-oriented design level (OO analysis, OO design and use of an OO database).
At the end of level 4, C programmers are thinking in the object-oriented paradigm and begin to rethink their programming design methodology.
This stuff takes time!