Chapter 1 Introduction to Computers, Programs, and C++.ppt

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1、Chapter1IntroductiontoComputers,Programs,andC+1.1Computer,Program,andOperatingSystems1.2ComputerProgramming1.3IntroductiontoC+ObjectiveslToreviewcomputerbasics,programs,andoperatingsystemslToknowtheconceptofcomputerprogramminglToknowthehistoryofC+lTowriteasimpleC+programlTounderstandtheC+programdeve

2、lopmentcycle21.1 Computer,Program,and OSAcomputerisamachinethatmanipulatesdataaccordingtoasetofinstructions.3CPUCentral Processing Unit(CPU),the brain of a computerIt retrieves instructions from memory and executes them The CPU speed is measured in megahertz,MHz The speed of a PC now is about 3 GHz(

3、3000 MHz)4MemoryMemory is to store data and program instructions for CPU to execute.A program and its data must be brought to memory before they can be executed.A memory unit is an ordered sequence of bytes,each holds eight bits.Memory is volatileData is lost when the power is off5Storage DevicesPro

4、grams and data are permanently stored on storage devicesThey are moved to memory when the computer needs them.There are three main types of storage devices:Disk drives(hard disks and floppy disks),CD drives(CD-R/W,DVD-R/W),and Tape drives.6How Data is Stored?lData:numbers,characters,andstringslCompu

5、tersuse“0”and“1”torepresentalldatalEncodinganddecodinglDatabinarycodelautomaticallydonebythecomputerlTheencodingschemevaries.lAbyte,of8bits,istheminimumstorageunit7Number Systems0,10,1,2,3,4,5,6,70,1,2,3,4,5,6,7,8,90,1,2,3,4,5,6,7,8,9,A,B,C,D,E,Fbinaryoctaldecimalhexdecimal8Input DeviceslAnypieceofc

6、omputerhardwareequipmentusedtoprovidedataandcontrolsignalstoacomputerlEarlydevices:punchedcardetc.lKeyboardslPointingdevices:mice,joysticks,pointstickslImagingandVideoinputdeviceslAudioinputdevicesl.9Output Devices:MonitorThe monitor displays information(text and graphics).The resolution and dot pit

7、ch determine the quality of the display.Resolution:specifies the number of pixels per square inch.Pixels(short for“picture elements”)are tiny dots that form an image on the screen.Dot pitch:the amount of space between pixels.The smaller the dot pitch,the better the display.10Communication DevicesDev

8、ices used to communicate with other computers/networks.Modems,devices make use of phone/TV line to connect to networkRegular modem,DSL modem,TV cable modem,mobile phone data modem Network interface card(NIC)is a device to connect a computer to a local area network(LAN)Cable NIC,Wireless NIC,Bluetoot

9、h NIC11Operating SystemslOperating system(OS):aprogramthatmanagesandcontrolsacomputersactivitieslMajorfunctionslProcessmanagementlMemorymanagementlDevicemanagementlFilesystem12Popular OSslMicrosoftWindowslOriginatedasanadd-ontotheMS-DOSlModernversionsarebasedonWindowsNTkernellUnixandUnix-likeOssladi

10、versegroupofoperatingsystems,includingSystemV,BSD,andLinuxlMacOSXlaUNIXoperatingsystembyAppleInc.lReal-timeoperatingsystemslEmbeddedsystems131.2 Computer ProgramminglComputerprograms,knownassoftware,areinstructionstothecomputer.lYoutellacomputerwhattodothroughprograms.lProgramsarewrittenusingprogram

11、minglanguages.lComputerProgramminglTheprocessofwriting,testing,debugging,andmaintainingthesourcecodeofcomputerprograms14Programming ProcedurelProblem-solvingphaselProblemanalysisandspecificationlGeneralsolution(algorithm)lVerificationlImplementationphaselConcretesolution(program)lDebuggingandtest15P

12、rogramming ParadigmlImperativeprogrammingDescribescomputationintermsofstatementsthatchangeaprogramstate.Describinghowtogoaboutaccomplishingatask.lProceduralprogramminglObject-orientedprogramminglDeclarativeprogrammingDescribingwhattheprogramshouldaccomplish.lFunctionalProgramminglLogicprogrammingl16

13、Programming LanguagelAnartificiallanguagetoexpressprogramlLanguageDefinitionlSyntaxldescribesthepossiblecombinationsofsymbolsthatformasyntacticallycorrectprogramlSemanticsldefinesrestrictionsonthestructureofvalidtextsMachineLanguageAssemblyLanguageHigh-LevelLanguage17Machine LanguagelMachinelanguage

14、isasetofprimitiveinstructionsbuiltintoeverycomputer.lTheinstructionsareintheformofbinarycode,soyouhavetoenterbinarycodesforvariousinstructions.lProgramwithnativemachinelanguageisatediousprocess.lMoreovertheprogramsarehighlydifficulttoreadandmodify.lForexample,toaddtwonumbers,youmightwriteaninstructi

15、oninbinarylikethis:110110101001101018Assembly LanguagelAsymbolicrepresentationofthenumericmachinecodeslassemblycode:instructionlCPUarchitecturedependentlAssembler,alsoaprogram,isusedtoconvertprogramsintomachinecode.lForexample,toaddtwonumbers:ADDF3R1,R2,R319High-level LanguageslLanguageswithnaturall

16、anguageelementslBeeasiertouselBemoreportableacrossplatforms.lhidethedetailsofCPUoperationssuchasmemoryaccessmodelslForexample:area=5*5*3.1415;lCompiledvs.interpretedlBASIC,Perl,lC,Java,20Popular LanguageslCOBOL:mainlyforinbusiness,finance,andadministrativesystemsforcompaniesandgovernmentslFORTRAN:ma

17、inlyforscientificcomputinglBASIC:BeginnerAll-purposeSymbolicInstructionalCodelVisualBasic:Basic-likevisuallanguagedevelopedbyMicrosoftlPascal:genericlanguagelDelphi:Pascal-likevisuallanguagedevelopedbyBorlandlAda:goodforembeddedandreal-timesystemslC:genericlanguage,strongatsystemprogramminglC+:anobj

18、ect-orientedlanguage,basedonClJava:C+likelanguage,Cross-platform(multi-platform)21Compiling Source CodelSource program:a programwritteninahigh-levellanguagelCompiler:aprogramusedtotranslatethesourceprogramintoanobject program,amachinelanguageprogram.lTheobjectprogramisoftenthenlinkedwithothersupport

19、inglibrarycodebeforeexecution.221.3 Introduction to C+lC,C+,Java,andC#areverysimilar.lC+evolvedfromC.lJavawasmodeledafterC+.lC#isasubsetofC+withsomefeaturessimilartoJava.lClanguageBlanguageBCPLlanguagelBCPLwasdevelopedbyMartinRichardsinthemid-1960sforwritingoperatingsystemsandcompilers.lC+ClDevelope

20、dbyBjarneStroustrupatBellLabsduring1983-1985.lC+addedanumberoffeaturesthatimprovedtheClanguage.lMostimportantly,itaddedtheclass.lAninternationalstandardforC+wascreatedbyAmericanNationalStandardsInstitute(ANSI)in1998.23A Simple C+Program#include int main()/Display Welcome to C+to the console std:cout

21、 Welcome to C+!std:endl;return 0;WelcomeRun24Extending the Simple C+Program#include int main()std:cout Welcome to C+!std:endl;std:cout Welcome to Visual C+!std:endl;std:cout Welcome to C+Compiler!std:endl;return 0;WelcomeRun25Procedure of Developing a C+Program26C+Programming ToolslCommandlinetoolslTexteditor+compilerlVisualtoolslC+builderlVisualC+lVisualStudio27SummarylBasicconceptsrelatedtocomputerprogramminglComputer,program,programminglComputerprogrammingtechniqueslProgramminglanguageslProgrammingParadigmslIntroductiontoC+28