Computer programming is the process or activity of developing programs, or lists of instructions, that control the operation of a computer. Programming may be broken down into stages: requirements definition, design specification, coding, testing, and maintenance. The requirements stage involves quantifying the necessary operations to be performed by the program. In the design-specification stage, directions are provided for meeting the requirements by quantifying the processing steps and the data-storage structures in greater detail. Coding is the stage in which the algorithms, data structures, and program design are turned into steps expressed in a chosen programming language. Particular care must be taken in this step to make certain the computer is given precise and correct (detailed) commands to carry out what the requirements demand. Testing is the stage in which the program is verified as being correct with respect to the requirements and design specification. A number of testing methods are applied to catch a variety of errors. After the program is tested and found to be correct, it is released to its users. The final stage is maintenance, in which enhancements and corrections are made. It is the most lengthy and costly stage of programming. To illustrate all these stages, consider the following design of a program to find the sum of a list of real numbers:

Marketing representative- Modern marketing has evolved into a complex and diverse field. This field includes a wide variety of special functions such as advertising, mail-order business, public relations, retailing and merchandising, sales, transportation, wholesaling, marketing research, and pricing of goods. The aim of marketing is to acquire, retain, and satisfy customers. Marketers begin by identifying the market for their product. Then they tailor their efforts to satisfy the needs and wants of customers within that market. A customer may be an industrial organization such as a food processor, a wholesale or retail outlet, a transportation or warehousing company, or an individual consumer. Those firms which understand the needs of their customers and seek to satisfy them tend to be more successful than those which do not.

Computer engineering is the profession that deals with the design and building of machines, devices, and structures. It is among the oldest of professions, although until perhaps the 18th century it was rarely distinguished from that of the scientist, the inventor, or the builder. In fact the histories of technology, science, and engineering were intertwined for many centuries--technology being in a sense the product of engineering, and science (the development of theories to explain natural phenomena) often being based on the empirical evidence supplied by the builders of machines and structures.

System Analyst, in computer science, the person responsible for administering use of a multi-user computer system, communications system, or both. A system administrator performs such duties as assigning user accounts and passwords, establishing security access levels, and allocating storage space, as well as being responsible for other tasks such as watching for unauthorized access and preventing virus or Trojan horse programs from entering the system.

An operator controls a computer. The operator has three major priorities: He coordinates and manipulates computer hardware, such as computer memory, printers, disks, keyboard, mouse, and monitor; organizes files on a variety of storage media, such as floppy disk, hard drive, compact disk, and tape; and manages hardware errors and the loss of data.

A data entry operator prompts the user (or other machines) for input and commands, reports the results of these commands and other operations, stores and manages data, and controls the sequence of the software and hardware actions. When the user requests that a program run, the operating system loads the program in the computer's memory and runs the program.

A computer technician aids in the maintenance and repair of the computer and it’s hardware.

The automobile industry, more accurately the motor vehicle industry, comprises the manufacture and assembly of automobiles, buses, motorcycles, trucks, and components of motor vehicles. The petroleum and rubber industries are not included, nor are manufacturers of batteries and other electrical equipment, unless they are affiliated with a motor vehicle company. The assembly-line technique introduced by Henry Ford continues to be used in Europe and America. Automation was introduced on the assembly line in the early 1950s, computer-controlled welding robots in the 1970s, and computerized machining of engine parts in the late 1980s.

Computer programs, or applications, exist to aid every level of education, from programs that teach simple addition or sentence construction to advanced calculus. Educators use computers to track grades and prepare notes; with computer-controlled projection units, they can add graphics, sound, and animation to their lectures. The United States and other countries have begun to take advantage of the ability of audiovisual devices to transcend geographical barriers. Audiovisual devices can expose students to experiences beyond the classroom, and they can disseminate instruction across large areas, making education accessible to more people. In the U.S., communication satellites distribute educational programming to all public television stations; some programs are broadcast and others may be viewed on closed-circuit systems. India has also experimented with satellites to broadcast educational materials. In England, the Open University provides a college education by using radio, television, and regional learning centers. Other nations that have used audiovisual devices to transmit educational materials over large distances are France, Canada, and Brazil. As the technology improves, educational capabilities increase correspondingly. The emergence of inexpensive computer technology and mass storage media, including optical video discs and compact disks, has given instructional technologists better tools with which to work. Compact disks (the CD-ROM and CD-I) are used to store large amounts of data, such as encyclopedias or motion pictures. At new interactive delivery stations with computers and CD-ROM, CD-I, or video discs, a student who is interested in a particular topic can first scan an electronic encyclopedia, then view a film on the subject or look at related topics at the touch of a button. These learning stations combine the advantages of reference materials, still pictures, motion pictures, television, and computer-aided instruction. With even newer technologies now being developed, such learning stations will eventually be commonplace in homes for both entertainment and educational purposes. With millions of personal computers and videocassette recorders in use in the U.S., teaching via these non-broadcast technologies is also growing rapidly. Electronic media offer the means for reaching populations that are homebound or geographically isolated.

Medicine- New and better methods of seeing inside the human body were developed in the latter half of the 20th century. In the 1970s a special camera sensitive to gamma radiation was developed for locating specific cancers. Diagnosis of head injury was aided greatly by the invention in 1975 of a computer-assisted X-ray device called a computerized axial tomography (CAT) scanner. Other imaging systems include positron emission tomography and nuclear magnetic resonance imaging.

In the home environment, computers can be used in many ways. They can be used for work or for pleasure. You can type reports for the office, type reports for school, connect to the Internet, browse an encyclopedia CD ROM. Anything is possible. You can get any information you need and computers can also gather and organize the information easily, saving time, energy, and money.

In office practice, computers are used to type up documents or reports, or gather information on a client or employee. They also can help teach you how to type faster. Information can be manually, electrically, or electronically produced, duplicated, and transmitted. Most modern office equipment includes typewriters, dictation equipment, facsimile machines, photocopiers, calculators, and telephone systems. Office documents are generally mechanically or electronically produced records: letters, spreadsheets, memos, invoices, and so on. These are produced on a variety of equipment, including typewriters, word processors, and computers, and may be saved on paper or in electronically encoded form.

Airline Industry, area of commerce in which aircraft are employed to carry passengers, freight, and mail. Air transport companies operate scheduled airlines and nonscheduled services over local, regional, national, and international routes. The aircraft operated by these companies range from small single-engine planes to large multiengine jet transports. A computer aids in booking fights. A small aircraft may have weather radar, and a full array of avionics (aeronautical electronics) on larger planes may rival the sophisticated equipment on commercial airliners. This would not be possible without the aid of computers.

Computer crime is generally defined as any crime accomplished through special knowledge of computer technology. Increasing instances of white-collar crime involve computers as more businesses automate and information becomes an important asset. Computers are objects of crime when they or their contents are damaged, as when terrorists attack computer centers with explosives or gasoline, or when a computer virus--a program capable of altering or erasing computer memory--is introduced into a computer system. As subjects of crime, computers represent the electronic environment in which frauds are programmed and executed. An example is the transfer of money balances in accounts to perpetrators' accounts for withdrawal. Computers are instruments of crime when used to plan or control such criminal acts as complex embezzlements or tax-evasion schemes over long periods of time, or when a computer operator uses a computer to steal valuable information from an employer. Computers have been used for most kinds of crime, including fraud, theft, larceny, embezzlement, burglary, sabotage, espionage, murder, and desktop forgery.

Software piracy is the unauthorized and illegal duplication of copyrighted computer software. The most common forms include copying for personal use, for use among employees of a company, and for resale. The latter includes the manufacturing of counterfeit packages that pretend to be originals. Piracy is the most widespread computer crime. The Software Publishers Association, the principal trade group of the personal computing software industry, estimated that in 1994 the industry lost $8.08 billion worldwide due to illegal copying of business software alone. This did not include illegal copying of operating systems, education, entertainment, or personal productivity software.

Hacking- A hacker, in the term's original, benign sense, is a computer enthusiast who takes much enjoyment in computer programming, solving problems with computers, trying to expand a computer's capabilities, learning all the details of a particular computer program, and so on--as contrasted with typical computer users, who usually are interested in learning only the minimum required to operate their machines. The term hacker also is sometimes applied to someone who tries to gain unauthorized access to computer systems, often with malicious intent. True hackers consider this a misuse of the term, and use "cracker" to describe such a person.

Access to confidential material- One technique to protect confidentiality is encryption. Information can be scrambled and unscrambled using mathematical equations and a secret code called a key. Two keys are usually employed, one to encode and the other to decode the information. The key that encodes the data, called the private key, is possessed by only the sender. The key that decodes the data, called the public key, may be possessed by several receivers. The keys are modified periodically, further hampering unauthorized access and making the encrypted information difficult to decode or forge.