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Wednesday, May 14, 2008

C++ Language FAQ

Frequently Asked Questions

What is C++?

C++ is a programming language. It literally means "increased C", reflecting its nature as an evolution of the C language.


Is it necessary to already know another programming language before learning C++?

Not necessarily. C++ is a simple and clear language in its expressions. It is true that a piece of code written with C++ may be seen by a stranger of programming a bit more cryptic than some other languages due to the intensive use of special characters ({}[]*&!|...), but once one knows the meaning of such characters it can be even more schematic and clear than other languages that rely more on English words.

Also, the simplification of the input/output interface of C++ in comparison to C and the incorporation of the standard template library in the language, makes the communication and manipulation of data in a program written in C++ as simple as in other languages, without losing the power it offers.

How can I learn C++?

There are many ways. Depending on the time you have and your preferences. The language is taught in many types of academic forms throughout the world, and can also be learnt by oneself with the help of tutorials and books. The documentation section of this Website contains an online tutorial to help you achieve the objective of learning this language.

What is OOP: Object-oriented programming?

It is a programming model that treats programming from a perspective where each component is considered an object, with its own properties and methods, replacing or complementing strutured programming paradigm, where the focus was on procedures and parameters.

Is C++ a propietary language?
No. No one owns the C++ language. Anyone can use the language royalty-free.

What is ANSI-C++?

ANSI-C++ is the name by which the international ANSI/ISO standard for the C++ language is known. But before this standard was published, C++ was already widely used and therefore there is a lot of code out there written in pre-standard C++. Referring to ANSI-C++ explicitly differenciates it from pre-standard C++ code, which is incompatible in some ways.

How may I know if my compiler supports ANSI-C++?

The standard was published in 1998, followed by a revision in 2003. Some compilers older than the standard implement already some of its features, and many newer compilers don't implement all ANSI-C++ features. If you have doubts on whether your compiler will be able to compile ANSI-C++ code, you can try to compile a piece of code with some of the new features introduced mainly after the publication of the standard. For example, the following code fragment uses the bool type, and uses namespaces and templates.

#include 
using namespace std;
template <class T>
bool ansisupported (T x) { return true; }

int main() {
if (ansisupported(0)) cout << "ANSI OK";
return 0;
}
ANSI OK

If your compiler is able to compile this program, you will be able to compile most of the existing ANSI-C++ code.

How can I make windowed programs?

You need a C++ compiler that can link code for your windowing environment (Windows, XWindow, MacOS, ...). Windowed programs do not generally use the console to communicate with the user. They use a set of functions or classes to manipulate windows instead, which are specific to each environment. Anyway the same principles apply both for console and windowed programs, except for communicating with the user.

What is Visual C++? And what does "visual programming" mean?
Visual C++ is the name of a C++ compiler with an integrated environment from Microsoft. It includes special tools that simplify the development of large applications as well as specific libraries that improve productivity. The use of these tools is generally known as visual programming. Other manufacturers also develop these types of tools and libraries, like Borland C++, Visual Age, etc...

History of C++



During the 60s, while computers were still in an early stage of development, many new programming languages appeared. Among them, ALGOL 60, was developed as an alternative to FORTRAN but taking from it some concepts of structured programming which would later inspire most procedural languages, such as CPL and its succesors (like C++). ALGOL 68 also directly influenced the development of data types in C. Nevertheless ALGOL was an non-specific language and its abstraction made it impractical to solve most commercial tasks.


In 1963 the CPL (Combined Programming language) appeared with the idea of being more specific for concrete programming tasks of that time than ALGOL or FORTRAN. Nevertheless this same specificity made it a big language and, therefore, difficult to learn and implement.


In 1967, Martin Richards developed the BCPL (Basic Combined Programming Language), that signified a simplification of CPL but kept most important features the language offered. Although it too was an abstract and somewhat large language.



In 1970, Ken Thompson, immersed in the development of UNIX at Bell Labs, created the B language. It was a port of BCPL for a specific machine and system (DEC PDP-7 and UNIX), and was adapted to his particular taste and necessities. The final result was an even greater simplification of CPL, although dependent on the system. It had great limitations, like it did not compile to executable code but threaded-code, which generates slower code in execution, and therefore was inadequate for the development of an operating system. Therefore, from 1971, Denis Ritchie, from the Bell Labs team, began the development of a B compiler which, among other things, was able to generate executable code directly. This "New B", finally called C, introduced in addition, some other new concepts to the language like data types (char).


In 1973, Denis Ritchie, had developed the basis of C. The inclusion of types, its handling, as well as the improvement of arrays and pointers, along with the later demonstrated capacity of portability without becoming a high-level language, contributed to the expansion of the C language. It was established with the book "The C Programming Language" by Brian Kernighan and Denis Ritchie, known as the White Book, and that served as de facto standard until the publication of formal ANSI standard (ANSI X3J11 committee) in 1989.


In 1980, Bjarne Stroustrup, from Bell labs, began the development of the C++ language, that would receive formally this name at the end of 1983, when its first manual was going to be published. In October 1985, the first commercial release of the language appeared as well as the first edition of the book "The C++ Programming Language" by Bjarne Stroustrup.


During the 80s, the C++ language was being refined until it became a language with its own personality. All that with very few losses of compatibility with the code with C, and without resigning to its most important characteristics. In fact, the ANSI standard for the C language published in 1989 took good part of the contributions of C++ to structured programming.


From 1990 on, ANSI committee X3J16 began the development of a specific standard for C++. In the period elapsed until the publication of the standard in 1998, C++ lived a great expansion in its use and today is the preferred language to develop professional applications on all platforms.


C++ has been evolving, and a new version of the standard, c++09, is being developed to be published before the end of 2009, with several new features.