Getting The C Language

A Brief History Of The C Language

You might be wondering about the origin of the C language and where it got its name. C was created by Dennis Ritchie at the Bell Telephone Laboratories in 1972. The language wasn’t created for the fun of it, but for a specific purpose: to design the UNIX operating system (which is used on many computers). From the beginning, C was intended to be useful—to allow busy programmers to get things done.

Because C is such a powerful and flexible language, its use quickly spread beyond Bell Labs. Programmers everywhere began using it to write all sorts of programs. Soon, however, different organizations began utilizing their own versions of C, and subtle differences between implementations started to cause programmers headaches. In response to this problem, the American National Standards Institute (ANSI) formed a committee in 1983 to establish a standard definition of C, which became known as ANSI Standard C. With few exceptions, every modern C compiler has the ability to adhere to this standard.

Now, what about the name? The C language is so named because its predecessor was called B. The B language was developed by Ken Thompson of Bell Labs. You should be able to guess why it was called B.


Why Use C ?

In to unit’s world of computer programming, there are many high-level languages to choose from, such as C, Pascal, BASIC, and Java. These are all excellent languages suited for most programming tasks. Even so, there are several reasons why many computer professionals feel that C is at the top of the list:· C is a powerful and flexible language. What you can accomplish with C is limited only by your imagination. The language itself places no constraints on you. C is used for projects as diverse as operating systems, word processors, graphics, spreadsheets, and even compilers for other languages. · C is a popular language preferred by professional programmers. As a result, a wide variety of C compilers and helpful accessories are available. · C is a portable language. Portable means that a C program written for one computer system (an IBM PC, for example) can be compiled and run on another system (a DEC VAX system, perhaps) with little or no modification. Portability is enhanced by the ANSI standard for C, the set of rules for C compilers. · C is a language of few words, containing only a handful of terms, called keywords, which serve as the base on which the language’s functionality is built. You might think that a language with more keywords (sometimes called reserved words) would be more powerful. This isn’t true. As you program with C, you will find that it can be programmed to do any task.

· C is modular. C code can (and should) be written in routines called functions. These functions can be reused in other applications or programs. By passing pieces of information to the functions, you can create useful, reusable code.

As these features show, C is an excellent choice for your first programming language. What about C++? You might have heard about C++ and the programming technique called object-oriented programming. Perhaps you’re wondering what the differences are between C and C++ and whether you should be teaching yourself C++ instead of C.

Not to worry! C++ is a superset of C, which means that C++ contains everything C does, plus new additions for object-oriented programming. If you do go on to learn C++, almost everything you learn about C will still apply to the C++ superset. In learning C, you are not only learning one of to unit’s most powerful and popular programming languages, but you are also preparing yourself for object-oriented programming.

Another language that has gotten lots of attention is Java. Java, like C++, is based on C. If later you decide to learn Java, you will find that almost everything you learned about C can be applied.


Preparing To Program

You should take certain steps when you’re solving a problem. First, you must define the problem. If you don’t know what the problem is, you can’t find a solution! Once you know what the problem is, you can devise a plan to fix it. Once you have a plan, you can usually implement it. Once the plan is implemented, you must test the results to see whether the problem is solved. This same logic can be applied to many other areas, including programming.
When creating a program in C (or for that matter, a computer program in any language), you should follow a similar sequence of steps:
1. Determine the objective(s) of the program.
2. Determine the methods you want to use in writing the program.
3. Create the program to solve the problem.
4. Run the program to see the results.
An example of an objective (see step 1) might be to write a word processor or database program. A much simpler objective is to display your name on the screen. If you didn’t have an objective, you wouldn’t be writing a program, so you already have the first step done.
The second step is to determine the method you want to use to write the program. Do you need a computer program to solve the problem? What information needs to be tracked? What formulas will be used? During this step, you should try to determine what you need to know and in what order the solution should be implemented.
As an example, assume that someone asks you to write a program to determine the area inside a circle. Step 1 is complete, because you know your objective: determine the area inside a circle. Step 2 is to determine what you need to know to ascertain the area. In this example, assume that the user of the program will provide the radius of the circle. Knowing this, you can apply the formula pr2 to obtain the answer. Now you have the pieces you need, so you can continue to steps 3 and 4, which are called the Program Development Cycle.
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