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Whence C? Why C? Whither C?
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Category: C / C++
Date: 29.01.2008 23:52:34
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As about ten years ago, C was the most popular programming language being used. Programmers wrote C code for PCs, mainframes, and supercomputers. C was standardized so that the same program would run on every kind of computer using every kind of operating system available.
Today, the use of C has dramatically decreased. Rarely will a project be written in C. Programmers are using languages such as C++ and Java to create applications that run on standalone, networked, and Internet-based machines. Yet, when learning to program, C is considered to be the one language it is imperative a programmer master before moving on to the other languages in use today.
The reason for C's recommended mastery, despite its low levels of actual use, is that C is the common denominator of many of today's languages; learn C and these languages will be simple to learn. Languages such as C++ and Java are based on C. In fact, many of the statements and commands in these newer languages are identical to the ones found in C. Overall, C is much simpler to learn than these languages because it carries with it a much slimmer toolkit of add-on procedures.
The article below is taken from the first chapter of the book "C Primer Plus, Fifth Edition, By Stephen Prata, 2004".
Whence C?
Dennis Ritchie of Bell Labs created C in 1972 as he and Ken Thompson worked on designing the Unix operating system. C didn't spring full-grown from Ritchie's head, however. It came from Thompson's B language, which came from… but that's another story. The important point is that C was created as a tool for working programmers, so its chief goal is to be a useful language.
Most languages aim to be useful, but they often have other concerns. The main goal for Pascal, for instance, was to provide a sound basis for teaching good programming principles. BASIC, on the other hand, was developed to resemble English so that it could be learned easily by students unfamiliar with computers. These are important goals, but they are not always compatible with pragmatic, workaday usefulness. C's development as a language designed for programmers, however, has made it one of the modern-day languages of choice.
Why C?
During the past three decades, C has become one of the most important and popular programming languages. It has grown because people try it and like it. In the past decade, many have moved from C to the more ambitious C++ language, but C is still an important language in its own right, as well a migration path to C++. As you learn C, you will recognize its many virtues (see Figure 1.1). Let's preview a few of them now.
Figure 1.1. The virtues of C.
Design Features
C is a good language incorporating the control features found desirable by the theory and practice of computer science. Its design makes it natural for top-down planning, structured programming, and modular design. The result is a more reliable, understandable program.
Efficiency
C is an efficient language. Its design takes advantage of the capabilities of current computers. C programs tend to be compact and to run quickly. In fact, C exhibits some of the fine control usually associated with an assembly language. (An assembly language is a mnemonic representation of the set of internal instructions used by a particular central processing unit design; different CPU families have different assembly languages.) If you choose, you can fine-tune your programs for maximum speed or most efficient use of memory.
Portability
C is a portable language, which means that C programs written on one system can be run on other systems with little or no modification. If modifications are necessary, they can often be made by simply changing a few entries in a header file accompanying the main program. Most languages are meant to be portable, but anyone who has converted an IBM PC BASIC program to Apple BASIC (and they are close cousins) or has tried to run an IBM mainframe FORTRAN program on a Unix system knows that porting is troublesome at best. C is a leader in portability. C compilers (programs that convert your C code into the instructions a computer uses internally) are available for about 40 systems, running from 8-bit microprocessors to Cray supercomputers. Note, however, that the portions of a program written specifically to access particular hardware devices, such as a display monitor, or special features of an operating system, such as Windows XP or OS X, typically are not portable.
Because of C's close ties with Unix, Unix systems typically come with a C compiler as part of the packages. Linux installations also usually include a C compiler. Several C compilers are available for personal computers, including PCs running various versions of Windows, and Macintoshes. So whether you are using a home computer, a professional workstation, or a mainframe, the chances are good that you can get a C compiler for your particular system.
Power and Flexibility
C is powerful and flexible (two favorite words in computer literature). For example, most of the powerful, flexible Unix operating system is written in C. Many compilers and interpreters for other languages—such as FORTRAN, Perl, Python, Pascal, LISP, Logo, and BASIC—have been written in C. As a result, when you use FORTRAN on a Unix machine, ultimately a C program has done the work of producing the final executable program. C programs have been used for solving physics and engineering problems and even for animating special effects for movies such as Gladiator.
Programmer Oriented
C is oriented to fulfill the needs of programmers. It gives you access to hardware, and it enables you to manipulate individual bits in memory. It has a rich selection of operators that allows you to express yourself succinctly. C is less strict than, say, Pascal in limiting what you can do. This flexibility is both an advantage and a danger. The advantage is that many tasks, such as converting forms of data, are much simpler in C. The danger is that with C, you can make mistakes that are impossible in some languages. C gives you more freedom, but it also puts more responsibility on you.
Also, most C implementations have a large library of useful C functions. These functions deal with many needs that a programmer commonly faces.
Shortcomings
C does have some faults. Often, as with people, faults and virtues are opposite sides of the same feature. For example, we've mentioned that C's freedom of expression also requires added responsibility. C's use of pointers (something you can look forward to learning about in this book), in particular, means that you can make programming errors that are very difficult to trace. As one computer preliterate once commented, the price of liberty is eternal vigilance.
C's conciseness combined with its wealth of operators make it possible to prepare code that is extremely difficult to follow. You aren't compelled to write obscure code, but the opportunity is there. After all, what other language has a yearly Obfuscated Code contest?
There are more virtues and, undoubtedly, a few more faults. Rather than delve further into the matter, let's move on to a new topic.
Whither C?
By the early 1980s, C was already a dominant language in the minicomputer world of Unix systems. Since then, it has spread to personal computers (microcomputers) and to mainframes (the big guys). See Figure 1.2. Many software houses use C as the preferred language for producing word processing programs, spreadsheets, compilers, and other products. These companies know that C produces compact and efficient programs. More important, they know that these programs will be easy to modify and easy to adapt to new models of computers.
Figure 1.2. Where C is used.
What's good for companies and C veterans is good for other users, too. More and more computer users have turned to C to secure its advantages for themselves. You don't have to be a computer professional to use C.
In the 1990s, many software houses began turning to the C++ language for large programming projects. C++ grafts object-oriented programming tools to the C language. (Object-oriented programming is a philosophy that attempts to mold the language to fit a problem instead of molding the problem to fit the language.) C++ is nearly a superset of C, meaning that any C program is, or nearly is, a valid C++ program, too. By learning C, you also learn much of C++.
Despite the popularity of newer languages, such as C++ and Java, C remains a core skill in the software business, typically ranking in the top 10 of desired skills. In particular, C has become popular for programming embedded systems. That is, it's used to program the increasingly common microprocessors found in automobiles, cameras, DVD players, and other modern conveniences. Also, C has been making inroads in FORTRAN's long dominance of scientific programming. Finally, as befits a language created to develop an operating system, it plays a strong role in the development of Linux. Thus, the first decade of the twenty-first century finds C still going strong.
In short, C is one of the most important programming languages and will continue to be so. If you want a job writing software, one of the first questions you should be able to answer yes to is "Oh say, can you C?"
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