Computer Graphics(Chapters 1&2)

Value of science in Everyday life

How is Science Used in Everyday Life?

How is science used in everyday life? It is all around us all of the time! The computer you're using- that's science! The air you're breathing- that's science too! The great thing about science is that it is constantly happening and there is always more to discover and learn. The things that we learn in science class in school give us a greater understanding of life and the world.

Value of science in Everyday life

Science has metamorphosed the very mode of our daily life. Science has stepped up the tempo of life; it has widened the range of our occupations, extended immensely the limits of our curiosity, it has increased the ways of utilising our leisure ; it has given us comforts and amenities undreamt of by our forefathers. Yet science is now the handmaiden of a privileged few who can purchase the service.

As regards our food, science has given us correct ideas of nutritive and calorie value of the food that we take. It has analysed and classified the various constituents of our diet according to vitamin content, caloric value, mineral basis etc. It has explained to us the factors that make a balanced diet. With the help of all this knowledge, the State can provide schoolchildren with cheap but nutritive food in order to build up the physique of future generations. This shows how much science can contribute to the improvement of national well-being. Science even has started producing synthetic food in the Laboratory, to supplement our food deficit.

Next item of our necessity is our dress. Modern science has taught us the utility of light dress in a tropical country. Our knowledge of science has helped up to manufacture dress materials more comfortable, more enduring and in the long run more economi­cal and adjusted to the prevailing environment. Today we are certainly better clothed than ever before.

Also science has shown us how we can do a greater volume of work in shorter time and with less physical strain and sweat. It has placed at our disposal innumerable labour-saving devices, so that, life can become far less difficult than it is.

Electric light and fan have made home-life more comfortable today. The typewriter, the computer, washing machine, the telephone, the motor car, refrigerator,-all these and many others show how much work we can do with minimum labour. They save us from the drudgery of manual work to recuperate and thus enable us to do much more work with greater output than our ancestors. At the same time, scientific process creates plenty of leisure, which we may devote to cultural pursuits. The modern man is thus able to live a fuller and many-sided life.

In our sickness, we feel more than ever the benefits of science. The physician and the surgeon are today much more sure in their diagnosis of diseases through clinical tests, brain scanning and supersonic devices. The physicians are now more confident in their ability to cure or to control them.

The microscope, the X-ray, the radium, ultra sonography—all these have come as real blessings to humanity. With the growth of chemical and bacteriological sciences, the treatment of diseases has been very much sophisticated and yet simplified. Wonder drugs like penicillin and streptomycin and other anti-biotics have proved specific medicines in the cure of diseases, which were formerly intractable.

Allied to this is the contribution that science has made to our ideas of sanitation and hygiene. Infectious diseases have been either completely eradicated, or brought under control, due to better sanitation and sewerage arrangements. Cholera, smallpox typhoids, aids and the like epidemic diseases have been largely tamed.

Other killing ailments like TB, Cancer, Coronary attacks are also consid­erably subdued, thanks to wonderful progress in medical research. Dysentery, typhoid etc. have ceased in countries, which believe in science and make its full use. Epidemic malaria has greatly been diminished. As a result of all these, the average expectation of human life has almost doubled in the last hundred years.

The services of science in providing us with cheap and innocent amusements are equally great. The radio, the television the cinema has helped to soothe our over-strained nerves with music and with means of refreshment and recreation. Equally delightful are the gramophone and cassette players. Outside home, we can drop in at a cinema-house and escape for a time from the worries of life. Even the theatre is something infinitely superior to what is used to be in the days of yatra. With the help of scientific devices of light focusing and the revolving stage, it is able to imitate, more convincingly, the realities of life.

Thus in our daily life science has been of the greatest help and benefits us in a variety of ways. It is difficult to say how much we owe to science in the affairs of our daily life. From morning to midnight we are served tirelessly by science and scientific devices.

Pretty much anything you do has some science underlying it. For instance, the computer on which you asked this question, as well as the Internet, are products of science.

Your radio, television, gamebox, and telephone are as well.

Using many of these devices does not require a knowledge of much science any more, however. Although to use a telephone, for instance, you have to have an understanding of logic, numbers, and geography (area codes), and setting up a gamebox requires a basic understanding of some principles of electrical and mechanical engineering.

There are other so many in daily life where your knowledge of science is applied directly:

Applied Mathematics:
* Using a calculator

* Calculating a tip in a restaurant in your heand
* Measuring ingredients or dimensions

Economics:
* Banking
* Writing checks
* Drawing up a budget/determining what you can afford
* Paying income or sales tax

Applied Physics:
* Cooking
* Baking
* Working out

Applied Cartography/Orienteering
* Choosing routes to drive, walk, or ride a balk
* Determining locations using addresses or milestones
* Hiking
* Using a map

Applied Semiotics or Linguistics
* Deciphering signs and symbols everywhere in life
* Deciding how to punctuate or write human speech
* Reading books or magazines

Nutritional Science:
* Preparing food and making decisions on what is good or bad to eat

Medical Science:
* Self-medicating (e.g. taking an aspirin or acetaminophin, etc.)
* Understanding potential interactions of over-the-counter products (e.g. knowing not to mix DayQuil or NyQuil with Tylenol, cough syrup, or antihistamine)
* Bandaging and basic triage (treating pimples, cuts, burns, bruises)
* Taking a temperature
* Stretching and preparing muscles for exercise
* Knowledge and application of proper hygiene
* Knowledge of diseases and how they are transmitted (e.g. flu, cold, chicken box, STDs, etc.)
* Knowledge of birth control and disease prevention

Sociology:
* Understanding how to behave in certain contexts
* Knowing what kinds of behavior to expect from others
* Understanding rules of etiquette and politeness in different contexts
* Following and understanding political discussions or news reports
* An awareness of how the individual fits into larger and larger groups of people

Psychology:
* Taking measures to improve one's own or someone else's mental health (e.g. exercise, relaxation, stress management, etc.

Celebrate Nepal

                                             

                                         Celebrate Nepal

Nava Barsha

The Nepalese Nava Barsha (New Year) day usually falls on the second week of April that is the first day of Baisakh in the Nepali calendar. The day is a national holiday and people celebrate it with great pomp. On this occasion, annual Bisket Jatra is also held in the city of Bhaktapur.

Dashain

 During the month of Kartik in the Bikram Sambat calendar (late September and early October), the Nepalese people indulge in the biggest festival of the year, Dashain. Dashain is the longest and the most auspicious festival in the Nepalese annual calendar, celebrated by Nepalese of all caste and creed throughout the country. The fifteen days of celebration occurs during the bright lunar fortnight ending on the day of the full moon.

Tihar

 Tihar, the festival of lights is one of the most dazzling of all Hindu festivals. In this festival we worship Goddess Laxmi, the Goddess of wealth. It heralds the month of Kartik (October/November) starting with Kukur Puja-Narak Chaturdashi.

Gaijatra (Cow Festival)

Gaijatra is held in the month July - August. It is a carnival type of festival lasting for seven days. Dancing, singing, comedy and anything that causes laughter are its highlights. Those people whose family members have died during the year send out persons dressed up as a cow to parade the main thoroughfare of the city on the second day of the festival.

Krishnastami

Krishnastami falls in the month of July - August. It marks the birthday of Lord Krishna, one of the incarnation of Lord Vishnu, an epic hero of the MAHABHARAT. On this day there is an impressive ceremony at Krishna Mandir temple of Patan City and Changu Narayan. Folk dances and songs are on this occasion.

Indra Jatra

Indra Jatra takes place in the month of August -September. This is the festival of Indra - the god of rain and is observed in the Kathmandu city with great enthusiasm. The celebration of this festival lasts for 7 days. The chariot of Kumari - the Living Goddess is taken out in the procession through the main streets of Kathmandu city three times within 7 days. The Kumari is placed on a decorated chariot which is pulled through the street by the devotees. The whole celebration is largely confined to the traditional market and residential areas of Kathmandu like Durbar Square of Hanuman Dhoka which echoes of beating of drums and dancing feet of the masked dancers almost every evening. The king always pays homage to the Living Goddess on this day.

 Buddha Jayanti

This day is celebrated to mark the birthday of the Lord Buddha which dates back in about 543 BC.It falls on Jestha Purnima (Full moon night-May/June).

Janai Purim, Rakshya Bandhan, Khumbeshwor Mela Patan

 Janai Purnima is the festival of Sacred Thread. On this day every Hindu ties a sacred thread on the wrist. It is also called Rakshya Bandhan.On this day, there is a big Mela (fair) at Khumbeshwor; Lalitpur.It is again on a full moon night.

Maghe Sankranti

Maghe Sankranti is the beginning of the holy month of Magh, usually the mid of January. It brings an end to the ill-omened month of Poush (mid-December) when all religious ceremonies are forbidden. Even if it is considered the coldest day of the year, it marks the coming of warmer weather and better days of health and fortune.

Shree Panchami

This festival falls in mid Magh (January/February).It is celebrated as the birthday of Saraswati, the Goddess of Learning. She is the lily-white daughter of Shiva and Durga in spotless white robe and seated in a full-blown lotus. This day is also dedicated to the martyrs of Nepal and hence celebrated as Martyr's Day.

Maha Shiva Ratri

This day is the celebration dedicated to the Lord Shiva which falls on the Trayodashi of the month Fagun (February/March).

Ghode Jatra

Ghode Jatra, the Horse Racing Day, falls on the month of March - April and this festival is known as the festival of horse race and entertainment. It is one of the cultural festival of the Kathmandu City.A grand horse parade takes place at Tundikhel, the central point of the city reputed to have been in the former days the largest parade ground in Asia. Horse races, acrobatic sports and military tattoo also take place at Tundikhel on this day. In other parts of this city, the various deities are carried shoulder-high on wheel less chariots, accompanied by traditional music.

Shree Ram Nawami

Ram Nawami is celebrated in the mid of Chaitra (March/April) as Lord Ram's Birthday. It is celebrated with much pomp at Janaki temple in Janakpur city, which lies in southern Nepal.

Chaite Dasain

Chaite Dasain used to be the original day of the grand Dasain festival (which takes place exactly six months later now), but because people got their stomachs upset after feasting on spicy food during the warm month of Chaitra, the grand celebration was shifted to the cooler season. But the religious fervor is still evident in the celebrations of the day.

Gaura Parva

Gaura Parva is another celebration honoring Lord Krishna's birthday. It is celebrated in far western Nepal with much gusto for two days (August/September). Apart from the many ceremonies that happen during this festival, it is the occasion for married women to put on the sacred thread. The deuda dance is a major part of the festivities in which participants hold hands and form a circle as they step to traditional music.

Guru Purnima

Teachers come second (after the gods) in the Hindu hierarchy of respect. The full moon day of the month June/July is set aside for students to pay homage to their teachers and receive blessings from them in return. At a place called Vyas on the Kathmandu-Pokhara highway, special worship is performed to Maharishi Vyas, the saint who wrote the great Hindu epic, Mahabharat. For Buddhists, the occasion (Dilla Punhi) is sacred as the day when the Buddha-to-be entered the womb of Queen Mayadevi. Religious functions are held at monasteries and temples to commemorate the event.

Lhosar

Lhosar is the Tibetan New Year which falls on February/March. This festival is mast impressively observed by all the Tibetan-speaking populations. They organize folk songs and dances on this occasion. These dances can be seen in Khumbu, Helambu and other northern regions of Nepal and also at Boudhanath in Kathmandu.

Rath Yatra

Biratnagar in south-eastern Nepal brings out a spectacular chariot procession to mark Lord Krishna's birthday (August/September). The parade sets out from the Radha Krishna temple and goes around the town. The six-meter tall chariot carries the images of Krishna and his consort Radha and is drawn by hordes of devotees. The annual chariot festival was started in 1932 to commemorate the building of a temple dedicated to Krishna.

Steps to protect your PC`s

Steps to protect your PC`s

1.  

Set up a password. This is key. You'll want a distinct password, I've been able to guess a lot of my friends' passwords, just to show them how easy it is. You'd be surprised how many people have their username as their password. So make the password a secret obsession you have, or something from your childhood or even a random object e.g.: 'CD case'.

2.  

Make others in your household an account. Almost 75% of the time, people will stop going into your account if you make them their own. Be sure to give them limited access, unless you want them to be able to access your account.

3.  

There is obviously still a chance that they'll get into your files and mess around. Here's what you do: go to your desktop. Right-click and make a compressed zipped folder. Name it Desktop Stuff or whatever you want. Put all of your desktop files except My Computer and Recycling Bin, into the file. Then go into the folder, and click file, add password. Add one, different from your username. It can be a simpler one, but not easy! if you are an advanced user, make a encrypted file container with FreeOTFE or truecrypt.

4.  

Go to My Documents, make a compressed zipped folder, named my documents, same thing, again different password.

5.  

If you don't want people to know your internet history, there are TWO things to do. One, set your History to 0 days to keep, by clicking Tools > Internet Options, in Internet Explorer. Also in Tools > Internet Options, clear your history every time after you use the Internet.

6.  

You don't want friends to get into any of your online accounts, right? Click Tools > Internet Options, again and go to Content on the top of the box. Click Auto Complete, and then clear passwords, and clear forms, and then uncheck all the little boxes, so they don't save again.

7.

For extra security, download Mozilla Firefox if you don't already have it. Parents won't check it, and it's easy to clear everything but your favorites - Tools, Clear Private Data.

8.

You can use Google Chrome Incognito feature for private internet browsing. Using this feature allows you to surf internet in a way that no history is saved in the browser.

9

For protection from password cracking programs such as Ophcrack, press the Windows key and R at the same time, type in syskey and press enter, choose update, select password startup, and type a password. This will encrypt your password with another password to make using software such as Ophcrack to crack the password much more difficult.

Cyber-crime& Security:

                                                         Cyber-crime& Security:

                                                                                                                                               

                                                                                                                                           Dinesh joshi

            Cyber crime is criminal activity done using computers and the Internet. This includes anything from downloading illegal music files to stealing millions of dollars from online bank accounts. Cyber- crime also includes non-monetary offenses, such as creating and distributing  viruses on other computers.It is one of the fastest growing areas of crime. More and more criminals are exploiting the speed. These include attacks against computer data and systems, identity theft, the distribution of child sexual abuse images, Bonnets  and various email scams such as phishing.

The most talked-about forms of computer crime usually deal with viruses and hacking into information systems to steal information or cause service interruptions or problems. Strangely enough, many forms of computer crime leave the criminal with only notoriety. That is not to say that computer crime does not frequently benefit the criminal (many steal money, services, software, information, etc.). However, many criminal attacks are nuisance ones where service is interrupted, viruses are transmitted, and Web site content is replaced with erroneous or embarrassing material. In many of these cases, the perpetrators are simply looking for a challenge. And unfortunately, no system is 100% secure. Even if it is well-protected from the outside world, insiders within the organization can quickly and easily wreak havoc if they so desire. All of the following fall into the category of computer crime or cyber crime:

      

    i.            Stealing someone's password by watching them type it in.

     ii.            Looking at someone's private files.

   iii.            Stealing computer media and hardware (disks, hard drives, etc.).

   iv.            Intercepting data.

    v.            Stealing information, money, or services.

   vi.            Impersonating someone else on a computer system.

 vii.            Creating or disseminating a computer virus.

viii.            Denying service by saturating a network.

   ix.            Hacking a Web site and replacing it with other material.

In the days of the old west, criminals would hide their faces, draw their guns and rob the local bank or stage-coach. These villains such as Bonnie and Clyde and Billy the Kid became famous for conducting robberies such as these. Over time the ways that money related crimes have evolved from strong-armed robberies to scams involving schemes for money. One of the few similarities is that the criminals have the money and the victims do not.While the basis for money related crimes have been pretty constant, the way that crimes are becoming more technologically creative. We have gone from in-person robberies to nameless and faceless crimes involving computers. By using computers and modern technology, people can scam people, steam identities, attempt email cons and a variety of other methods. However, these are not the only problems associated with computers.

Computer related crimes cover a wide array of issues for computer users. Crimes such as spamming, passing on computer viruses, harassment, cyber-stalking and others have become common in our modern world. While some of these issues do not carry potential monetary loss, they are just as harmful in the possibility of losing files, information and access to your computer.

Now a days it is important to all that , be careful when we are with in Internet.It is certainly not easy, but there are methods to cut down on computer crime. Entire departments within organizations specialize in this area, but it is still very important to know the basics for your own personal security.

• The first rule of thumb is to stay well-informed. Go to the hardware and software manufacturers' Web sites and read their security updates. They may very well have an update for a system you are using that fixes a security hole.
• Update your virus protection software often - at least once a week.
• Make sure you are using the encryption available to you. Many email clients have built-in encryption, but it has to be turned on to take advantage of it.
• Don't open suspicious email attachments. Always look at the three-letter file extension (for example, .doc is a Microsoft Word document and probably not a virus, however .exe or .vbs are programs or scripts that could potentially be viruses that will run when you open them).
• Change your passwords frequently and never give them out to anyone! Use passwords that are at least 6 characters and do not contain words in the dictionary. Also, don't choose something that would be obvious to someone who knows you (e.g. your dog's name). Use a combination of numbers, special characters, lower case letters, and upper case letters. For example, the password "J6b&Awm8" is much better than the password "spot".
• Don't give out any personal information that you wouldn't want the rest of the world to know.
• Ask your Internet service provider what measures are being taken to secure your personal Web space.
• Don't leave your computer unattended after logging in. (And, always log out when you are finished!)
• Back up your files very regularly (preferably to an off-site location).

The Internet’s not a place without crime, but it’s also not a place where you’re helpless. As this article points out, there’s lots you can do to protect yourself and your family on the Internet.

Fresh water is essential for life:

Fresh water is essential for life:

Yet, merely 3 percent of the water on Earth is fresh — and most of that is locked up in glaciers or deep underground. Imagine all of the world's water — oceans, rivers, lakes, glaciers — was represented by something the size of a standard globe; its fresh water would be just a marble-sized drop.

Fresh water also harbors the greatest concentration of life on Earth — greater than either terrestrial or marine biomes. Though it covers less than a fraction of 1 percent of the Earth's surface, fresh water provides habitat for more than 10 percent of known animals and about one-third of all known vertebrate species. And, more than 40 percent of all fish species are found in fresh water — even though it is, relatively speaking, a drop in the bucket.

The health and abundance of these species is a crucial indicator of the health of freshwater ecosystems. These ecosystems, in turn, play an important role in moderating the location, distribution, and timing of freshwater flows, ensuring that we receive a multitude of benefits and services.

Americans consume 99 gallons of water daily. And one out of six gallons served by U.S. water utilities finds its way back to the ground, leaking out of pipes or otherwise wasted. We protect only 35 percent of the upland areas that secure delivery of freshwater services downstream.

An ever-worsening water crisis demands that we respond with combined water efficiency and ecosystem management solutions to maintain freshwater species and services. Failure is simply not an option — at the current rate, we will degrade the remaining 11 percent of ecosystems that provide us with fresh water services by 2050.

Importance of water:

•       Agriculture uses a huge amount of water, more than 70 percent of available surface water each year.
•       Nearly 40 percent of the rivers in the U.S. are too polluted for fishing and swimming.
•       Nutrient runoff from agriculture has created algal blooms that deplete oxygen from the water and result in dead zones.
•       Nearly every major river in the world has been dammed, altering natural freshwater flows, cutting off migration routes and depleting fisheries downstream.
•       We have already lost more than half of our planet's wetlands and an estimated 30 percent of  freshwater species.
•      Sixty-nine percent of river catchments, responsible for the capture and provision of our freshwater supply, remain unprotected — putting more than two-thirds of the source areas of our rivers at risk.
•       Declines in native species and changes in freshwater food webs have been estimated to exceed US $100 million in lost income revenues.
•      In the next few decades, more than half of the world's people are expected to live with severe water scarcity.
•      Climate change, a growing global population, and increasing demands on water due to higher  standards of living threaten to further burden our planet's freshwater systems.

Freshwater Ecosystem Services:

•        drinking water
•        water for bathing/sanitation
•        water for food productionhydroelectric power generation
•        water purification and waste removal
•        nutrient cycling
•        transportation
•        recreation
•        flood control
•        climate regulation

Origination of C-Programming Language

Origination of C-Programming Language and getting its Name

To understand programming language you must be familiar with two words programming and language. Language is the collection of symbols, marks, sounds, gestures, icons and pictures that have special meaning and are used by people(may even be any creature) for sharing emotions or information among them. Programming is the process of listing the jobs in a sequence that something/somebody should have to be performed. So, programming language is the collection of notations for describing computation to people and to the machines.

C

 is a general-purpose programming language initially developed by Dennis Ritchie between 1969-1972; many of its principles and ideas were taken from earlier language B and B’s earlier ancestors CPL (Combined Programming Language) and BCPL(Basic Combined Programming Language); which are developed by Martin Richards. CPL was developed with the purpose of creating languages that were capable of both high level, machine independent programming and would still allow the programmer to control the behavior of individual bits of information. One major drawback of CPL was that it was too large for use in many applications. In 1967, BCPL was created as scaled down version of CPL while still retaining its basic features. In 1970 Ken Thomson, while working at Bell Labs, took this process further by developing the B language. B was the scaled down version of BCPL written specially for use in system programming.  Finally in 1972, a coworker of Ken Thomson, Dennis Ritchie, returned some of the generality found in BCPL to the B language in the process of developing the language we now know as C. The logic behind the name of B-programming was that it was first scaled down version of BCPL so B was used to represent the first scaled down version and was the first character of BCPL; and C-programming is the second scaled down version of BCPL and it uses the second character of the BCPL to represent the whole programming language .

C’s power and flexibility soon became apparent.  Because of this, the UNIX operating system which was originally written in assembly language, was almost immediately re-written in C. During the rest of 1970’s, C spread throughout many colleges and universities because of it’s close ties to UNIX and availability of C compiler.

The origin of C is closely tied to the development of the UNIX operating system, originally implemented in assembly language in PDP-7 by Ritchie and Thomson, incorporating several ideas from colleagues. Eventually they decided to port the operating system to PDP-11. B’s inability to take advantages of some of the PDP-11’s features, notably byte addressability, led to the development of an early version of C.

The original PDP-11 version of the UNIX was developed in assembly language. By 1973, with the addition of struct types, the C language had become powerful enough that most operating system kernel implemented in language other than assembly.

K&R C

In 1978, Brian Kernighan and Dennis Ritchie published the first edition of The Programming Language. This book was known to C programmers as “K&R” and served as an informal specification of the language. The version of C that describes is commonly referred as K&R C. The second edition of the book covers the ANSI C standard.

K&R introduced several features and are listed below-

a)     Standard I/O library,

b)     long int data type,

c)     unsigned int data type

d)     compound assignment operators of the form =op(such as =-) were changed to the form op= to remove the semantic ambiguity created by such construct  as i=-10, which had been interpreted as i=   -10.

Even after the publication of the 1989, C standard, for many years K&R C was still considered the “lowest common denominator” to which C programmers restricted themselves when maximum portability was desired; since many older compilers were still in use, and because carefully written k&R C can be legal standard C as well.

In early versions of C, only functions that returned a non-int value needed to be declared if used before the function definition; a function used without any previous declaration was assumed to return type int.

In the years following the publication of K&R C, several unofficial features were added to the language, supported by compilers from AT&T and some other vendors. These included:

a)     void functions(i.e. function with no return value).

b)     Functions returning struct or union types (rather than pointer).

c)     Assignment for struct data type.

d)     Enumerated type.

The large number of extensions and lack of agreement on a standard library, together with the language popularity implemented the K&R specification, led to the necessity of standardization.

ANSI C and ISO C

During late 1970s and 1980s version of C were implemented for wide variety of mainframe computers, minicomputers and microcomputers, including the IBM PC, as its popularity began increase significantly.

In 1983, the American National Standards Institute(ANSI) formed a committee, X3J11, to establish a standard specification of C. X3J11 based the C standard in the UNIX implementation; however, the non-portable portion of the UNIX C library was handed off to the IEEE working group 1003 to become the basis for the 1988 POSIX standard. In 1989, the C standard was ratified as ANSI X3 159-1989 “Programming Language C”. This version of language is often referred to as ANSI C, or C89.

In 1990, the ANSI C standard(with formatting changes) was adopted by International Organization for Standardization(ISO) as ISO/ICE 9899:1990, which is sometime called C90. Therefore, the term C89 and C90 refer to same programming language.

ANSI like other national standards bodies, no longer develops the C standard independently, but defers to the international C standard maintained by the working group ISO/ICE JTC1/SC22/WJ14. National adaptation of an update to international standard typically occurs within a year of ISO publication.

One of the C standardization process was to produce the superset of K&R C, incorporating many of the unofficial features subsequently introduced. The standard committee also included several additional features such as function prototype(borrowed from C++), void pointers, supports for international character sets and locales, and processor enhancements. Although the syntax for parameter declaration was argumented to include the style used in C++, the K&R interface continued to be permitted, for compatibility with existing source code.

C89 is supported by current C compilers, and most C code being written today is based on it. Any program written only in standard C and without any hardware dependent assumption will run correctly on any platform with a confirming C implementation, with in its resource limits without such precautions, programs may compile only on certain platform or with a particular compiler.

C99

After the ANSI/ISO standardization process, the C Language specification remained relatively static for several years. In 1995 Normative Amendment 1 to the 1990 C standard was published, to correct some details and to add more extensive support for international character sets. The C standard was further revised in the late 1990’s, leading to the publication of ISO 9899:1999 in 1999, which is commonly referred to as “C99”.  It has since been amended three times by Technical Corrigenda.

C99 introduced several new features, including inline functions, several new data types (including long long int and a complex type to represent complex number), variable-length arrays, improved support for IEEE 754 floating point, support for varadic macros, and support for on-line comments beginning with //, as in BCPL or C++. Many of these had already been implemented as extensions in several C compilers.

C99 is for the most part backward compatible with C90, but stricter in some ways; in particular, a declaration that lacks a type specifier no longer has int implicitly assumed. A standard macro –STDC-VERSION- is defined with values 1999011 to indicate that C99 support is available GCC, Solaris Studio, and other C compilers now support many or all of the new features of C99.

C11

In 2007, work began on another revision of the C standard informally called “C1X” until its official publication on 2011-12-08. The C standards committee adopted guidelines to limit the adaption of new features that had not been tested existing implementations.

The C11 standard adds numerous new features of C and the library, including type generic macro, anonymous structures, improved Unicode support, atomic operations, multi-threading, and bounds-checked functions. It also makes some portions of the existing C99 library optional and compatibility with C++.

Embedded C

Historically, embedded C programming requires nonstandard extensions to the C language in order to support exotic features such as fixed-point arithmetic, multiple distinct memory banks, and basic I/O operations.

In 2008, the C standards committee published a technical report extending the C language to address these issues by providing a common standard for all implementations to adhere to. It includes a number of features not available in normal C, such as fixed-point arithmetic, named address spaces, and basic I/O hardware addressing.

C is not a very low level language, nor a big one, and is not specialized to any particular area of application. But its absence of restriction and its generality make it more convenient and effective for many tasks than supposedly more powerful languages. C is middle level language; this doesnot mean that C is less powerful, harder to use, or less of less developed. Instead C combines the advantages of a high-level language with the functionalism of assembly language. Like the higher-level language, C provides block structures, standalone functions, and some small amount of data typing. It allows the manipulation of bits, bytes, words, and pointers, like assembly but it abstracts the hardware away from the code so that something written in C is very portable, meaning that a program can be easily adapted to run on several different computers. This is the great thing for system programmers; they can get the efficiency of assembly language programming without all the fuss and then they have a highly portable program; it allows programmers to do many things that probably would be caught as errors in high-level language. This is both an advantage and disadvantage. For the inexperienced programmer, it may be confusing when the behavior of a program is not correct. A high-level language catches many more possible errors at compile time, C lacks the highly typed environment that characterizes high-level languages.

According to Brian Kernighan co-author with Dennis Ritchie of “The C Programming Language”.; “Although the absence of some of features may seems like a grave of deficiency … keeping the language down to modest size has real benefits.” Since, C is relatively small; it can be described in small space and learned quickly. It has only 32 keywords to learn and support all type of conversion (QBASIC has 159 keywords).

Uses of C

C was initially used for system development work. But why use C…???? mainly because it produces code that run nearly as fast as written in assembly language. C is mostly used for writing the following types of programming:

            -Operating System                           -Text Editors

            -Language Compilers                      -Printer Spoolers

            -Assembly                                         -Network Drivers

            -Databases                                         -Utilities

Importance/Advantages of programming in C

1)     Easy to understand

2)     Freedom of using different type of data.

3)     Short listed words could be use.

4)     Efficient and fast programming.

5)     It can be used as mid-level language.

6)     Any type of software and operating system be developed with the help of C language.

All fields have technical words. These words are useful when you communicate with people in your field. But they do not communicate with outsiders. C also has its own technical words and reserved for self maintenance with special meaning and referred as keywords or reserved words. All of keywords are listed below with corresponding version’s amendment.

Below this can be ignored

C89 has 32 keyboards

auto                                                    extern                                     sizeof

break                                                  float                                        static

case                                                    for                                           struct

char                                                    goto                                        switch

const                                                   if                                             typedef

continue                                             int                                           union

default                                                long                                        unsigned

do                                                        register                                   void

double                                                            return                                     volatile

else                                                     short                                       while

enum                                                  signed

C99 adds five more keyboards

            _bool                                                  inline

            _complex                                           restrict

            _imaginary

C11 add seven more keywords

            _Alignas                                            _Noreturn

            _alignof                                             _Static_Assert

            _Atomic                                             _thread_local

            _generic