Encyclopedia of Computer Science and Technology

460 structured programmingsuited for distributed computing and parallel programmingwhere there were many separate entities running at thesame time.However, Simula was fairly obscure, and it was unlikelythat the large community of systems programmers whowere using C would switch to a totally different language.Instead, starting in the early 1980s, Stroustrup decided toadd object-oriented features (such as classes with memberfunctions, user-defined operators, and inheritance) to C. Atfirst he gave the language the rather unwieldy name of “Cwith Classes.” However, in 1985 he changed the name toC++. (The ++ is a reference to an operator in C that adds oneto its operand, thus C++ is “C with added features.”)At first some critics criticized C++ for retaining most ofthe non-object oriented features of C (unlike pure objectlanguages such as Smalltalk), while others complainedthat the overhead required in processing classes made C++slower than C. During the 1990s, however, C++ becameincreasingly popular, aided by its relatively smooth learningcurve for C programmers and the development or moreefficient compilers. C++ is now the most widely used generalpurpose computer language.Stroustrup has been honored for his contributions tocomputer science. In 1993 he received the ACM Grace HopperAward for his work on C++, and became an AT&TFellow. After leaving AT&T Stroustrup became a professorholding the College of Engineering Chair in Computer Scienceat Texas A&M University. In 2004 Stroustrup receivedthe IEEE Computer Society Computer EntrepreneurAward, and in 2005 the William Procter Prize for ScientificAchievement.Further ReadingBjarne Stroustrup [home page]. Available online. URL: http://parasol.tamu.edu/people/bs/.Accessed August 22, 2007.Dolya, Aleksey. “Interview with Bjarne Stroustrup.” Linux Journal,August 28, 2003. Available online. URL: http://www.linuxjournal.com/article/7099. Accessed August 22, 2007.Pontin, Jason. “The Problem with Programming: Bjarne Stroustrup,the Inventor of the C++ Programming Language, DefendsHis Legacy and Examines What’s Wrong with Most SoftwareCode.” Technology Review, November 28, 2006. Availableonline. URL: http://www.techreview.com/Infotech/17831/page1/. Accessed August 22, 2007.Stroustrup, Bjarne. The C++ Programming Language. Special 3rded. Upper Saddle River, N.J.: Addison-Wesley, 1997.———. The Design and Evolution of C++. Reading, Mass.: Addison-Wesley, 1995.structured programmingAs programs grew longer and more complex during the1960s, computer scientists began to pay more attention tothe ways in which programs were organized. Most programminglanguages had a statement called “GOTO” or itsequivalent. This statement transfers control to some arbitraryother point in the program, as identified by a label orline number.In 1968, computer scientist Edsger Dijkstra (see dijkstra,edsger) sent a letter to the editor of the Proceedings ofthe ACM with the title “GO TO Statement Considered Harmful.”In it he pointed out that the more such jumps programsmade from place to place, the harder it was for someone tounderstand the logic of the program’s operation.The following year, Dijkstra introduced the term structuredprogramming to refer to a set of principles for writingwell-organized programs that could be more easily shownto be correct. One of these principles is statements such asIf . . . Then . . . Else be used to organize a choice betweentwo or more alternatives (see branching statements) andthat statements such as While be used to control repetitionor iteration of a statement (see loop).Other computer scientists added further principles, suchas modularization (breaking down a program into separateprocedures, such as for data input, different stages of processing,and output or printing). Modularization makes iteasier to figure out which part of a program may be causing aproblem, and to fix part of a problem without affecting otherparts. A related principle, information hiding, keeps the dataused by a procedure “hidden” in that procedure so that itcan’t be changed from some other part of the program.Structured programming also encourages stepwiserefinement, a program design process described by NiklausWirth, creator of Pascal. This is a top-down approach inwhich the stages of processing are first described in highlevelterms (see also pseudocode), and then graduallyfleshed out in their details, much like the writing of anoutline for a book.The principles of structured programming were soonembodied in a new generation of programming languages(see Algol, Pascal, and c). Although use of well-structuredlanguage didn’t guarantee good structured programmingpractice, it at least made the tools available.The ideas of structured programming form a solid basisfor programming style today. They have been supplementedrather than replaced by a new paradigm developed in the1970s and 1980s (see object-oriented programming).Further ReadingDhal, Ole-Johan, Edsger W. Dijkstra, and C. A. R. Hoare, eds.Structured Programming. New York: Academic Press, 1972.Dijkstra, Edsger. A Discipline of Programming. Englewood Cliffs,N.J.: Prentice Hall, 1976.———. “Go To Statement Considered Harmful.” Communicationsof the ACM 11, no. 3 (1968): 147–148.———. “Notes on Structured Programming.” Available online. URL:http://www.cs.utexas.edu/users/EWD/ewd02xx/EWD249.PDF.Accessed August 22, 2007.Orr, Kenneth T. Structured Systems Development. New York: YourdonPress, 1977.Sun MicrosystemsFounded in 1982, Sun Microsystems (NASDAQ symbol:JAVA) has played an important role in the developmentof computer workstations and servers, UNIX-based operatingsystems, and the Java programming language (see Java,unix, and workstation).During the 1980s, Sun was known mainly for its workstationsfor programmers and graphics professionals, runningon its own SPARC series microprocessors. However,