Chapter1：

BasisofProgramDesignInstructor:XiangXieOutline1.1ProgramsandProgrammingLanguage

1.2ProgramDesignandAlgorithmsComputersystemHardwareSoftwareProgramsComputersystemHardwareSoftwareprogramsdatadocumentsProgram(Aseriesofcomputercommands)

Program=DataStructure+AlgorithmprogramminglanguageAsetofrulesandsymbolstocommunicatewithComputerAsetofprogramsProgramDesignPrograms#include<stdio.h>voidmain(){ printf(“whatareyoudoing?\n”);}ProgramsProgramminglanguageSoftwareProgramsLanguagerulesComputersystemHardwareSoftwareprogramsdatadocumentsProgram(Aseriesofcomputercommands)

Program=DataStructure+AlgorithmprogramminglanguageProgramsProgramsProgramalistof

instructions

forthecomputertofollowtoaccomplishthetaskofprocessingdataintoinformationProgrammingsimplymeanstellingacomputerwhattodo

Instructions（指令）madeupofstatements（語句）

usedinaprogramminglanguageComputersystemHardwareSoftwareprogramdatadocumentprogramminglanguageProgramsProgrammingLanguageNaturalLanguageUsedtocommunicate betweenpeopleProgrammingLanguageUsedtocommunicatebetween

people

andcomputerGrammarMeaningSyntax(語法)semantics(語義)ProgrammingLanguageThesyntax(語法)ofaprogramminglanguageisconcernedwiththeformofprogramsThesemantics(語義)

ofaprogramminglanguageisconcernedwiththemeaningofprogramsChinese,English,Germany,……

Fortran,B,Pascal,C,C++,Java,……ProgrammingLanguage1960Algol-601963CPL1967

BCPL1970B1972C1985C++19501960197019801990FortranAlgol-60CobolSimulaPascalSmalltalkAdaCC++JavaCPLBCPLB1995JAVA2000C#2000C#Outline1.1ProgramsandProgrammingLanguage

1.2ProgramDesignandAlgorithmsComputersystemHardwareSoftwareprogramdatadocumentprogramminglanguageProgramDesignProgramDesignProgramDesignaprocess/behaviordescribeshowtosolvetheproblemincludes

FOURstepsAnalyzeConfirmProgramDatastructureand

AlgorithmProblemDebugProgramminglanguageResultStepsKeywordsAlgorithm(算法)aseriesofstepsorprocedurestosolvetheproblemForeachproblem,therewouldbemanysolvingmethodsandstepsAlgorithmdecidesthequalityoftheprograme.g.Algorithm(算法)Essentialfactors:Operate+ControlArithmeticOperate:

＋－×÷LogicalOperate:and(與)、or(或)、not(非)RelationalOperate:

＞＜≥≤≡≠TransmitOperate:input、output、assignsequence

OperateControldecision(branch)

repetition(loop)

ExampleTherearetwoinkbottles,blueandblack,butwithwrongcolorsofinkinthem.Nowweneedtocorrectthefault.Algorithmanalysis:Notanumericproblem;Importanotherinkbottle,suchasred.①Fillblueinkinblackbottleintoredbottle②Fillblackinkinbluebottleintoblackbottle③Fillblueinkinredbottleintobluebottle④ChangeendDescriptionofAlgorithmsDifferentmethods:NaturallanguageTraditionalflowchartStructuredflowchartPseudocodeProblemAnalysisDiagram(PAD)DescriptionofAlgorithms

withFlowChartANSI(AmericanNationalStandardInstitute)CommonFlowChartSymbolsTerminatorDecisionProcessDataCommentsFlowLineConnectorInputa,ba->cb->ac->bStartOutputa,bEnde.g.ExchangetwonumbersThreeBasicStructures

ofProgramsSequentialS1S2abThreeBasicStructures

ofProgramsSelection

ConStat1Stat2YNBidirectionalChoice

StatNConYSingleDirectionalChoiceCon:ConditionStat:StatementThreeBasicStructures

ofProgramsLoopBodyNConYWhileLoopUntilLoopConNYBodye.g.5!

t=1開始t2tt3tt4tt5t輸出t結(jié)束DescriptionofAlgorithms

withFlowChartDisadvantage:N-SFlowChartN-SFlowChartConYNS1S22.Selection1.SequentialS1S23.Loop

LoopBodyLoopBodyWhenmatchConUntilmatchConWhileLoopUntilLoopExample0t,1it+iti+1iUntili>100Outputti>100NoYesStart0t,1it+iti+1iOutputtEndDesignofAlgorithms