Introductory Programming in C# Release 1.0 Andrew N. Harrington and George K. Thiruvathukal

224 Pages·2012·1.5 MB·English

Introductory Programming in C#
Release 1.0
Andrew N. Harrington and George K. Thiruvathukal
May29,2012

CONTENTS
1 Context 1
1.1 IntroductiontotheNotes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 CommentsonMilesChapter1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 C#DataandOperations 3
2.1 DevelopmentTools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 LabExercise: Editing,Compiling,andRunning . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3 CommentsonMilesSimpleData . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.4 DivisionandRemainders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.5 SubstitutionsinConsole.WriteLine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.6 LearningtoSolveProblems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.7 Lab: DivisionSentences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.8 Homework: GradeCalculation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3 DefiningFunctionsofyourOwn 23
3.1 SyntaxTemplateTypography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2 AFirstFunctionDefinition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.3 MultipleFunctionDefinitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.4 FunctionParameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.5 MultipleFunctionParameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.6 ReturnedFunctionValues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.7 TwoRoles: WriterandConsumerofFunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.8 LocalScope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.9 StaticVariables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.10 NotusingReturnValues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4 BasicStringOperations 37
4.1 StringIndexing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.2 SomeInstanceMethodsandtheLengthProperty . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.3 ACreativeProblemSolution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.4 Lab: StringOperations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5 Decisions 43
5.1 ConditionsI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.2 SimpleifStatements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.3 if-elseStatements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.4 MoreConditionalExpressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
5.5 MultipleTestsandif-elseStatements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
5.6 If-statementPitfalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
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5.7 CompoundBooleanExpressions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
6 WhileLoops 55
6.1 While-Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.2 While-StatementswithSequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
6.3 InteractivewhileLoops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6.4 Short-Circuiting&&and|| . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6.5 WhileExamples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
6.6 MoreStringMethods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
6.7 AlgorithmsusingWhile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.8 Do-WhileLoops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
6.9 NumberGuessingGameLab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.10 Homework: GradeCalculationfromIndividualScores . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.11 Lab: UsingMonoDevelop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
6.12 Lab: VersionControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
7 ForeachLoops 107
7.1 foreachSyntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
7.2 foreachExamples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
8 ForLoops 109
8.1 For-StatementSyntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
8.2 ExamplesWithforStatements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
9 Files 119
9.1 FileSyntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
9.2 GradeFileHomework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
10 Arrays 127
10.1 OneDimensionalArrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
10.2 MusicalScalesandArrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
10.3 LinearSearching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
10.4 SortingAlgorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
10.5 BinarySearching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
10.6 Lab: Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
10.7 Lab: Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
10.8 Multi-dimensionalArrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
11 Lists 159
11.1 ListSyntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
11.2 .NetLibrary(API) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
12 Dictionaries 163
12.1 DictionarySyntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
12.2 DictionaryEfficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
12.3 DictionaryExamples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
12.4 Lab: FileDataandCollections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
13 Classes 171
13.1 AFirstClassExample: Rational . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
13.2 ClassesAndStructs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
13.3 ClassExamples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
13.4 BookListAssignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
13.5 MercurialandTeamwork. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
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14 Interfaces 189
14.1 FractionsRevisited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
14.2 CSProjRevisited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
14.3 GroupGameProject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
15 Testing 201
15.1 Assertions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
15.2 Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
15.3 TestingtheConstructor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
15.4 TestingRationalComparisons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
15.5 TestingRationalArithmetic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
15.6 TestingRationalConversions(toothertypes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
15.7 TestingtheParsingFeature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
15.8 RunningtheTests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
16 Acknowledgements 207
17 ChangeLog 209
18 TODO’s 211
Index 213
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CHAPTER
ONE
CONTEXT
1.1 Introduction to the Notes
These notes are designed for Comp 170. They are closely tied to the excellent C# introduction in Rob Miles’ free
onlineC#YellowBook.
Thesenoteswillfollowmostlythesameorder,addingsomeextraexplanations,examples,andchallenges,andintro-
ducetheMonoopensourceimplementationofC#.
ThecontentherewillbeinterspersedwithcommentsaboutwheretolookatpartsofMilesbook,withclarificationsof
thebookandcommentsaboutwhatisnotimportantforabeginnerinthebook.
Computerprogramsaredesignedtorunonacomputerandsolveproblems. Thoughtheinitialproblemswillbetiny
andoftensilly,theywillserveaslearningtoolstoprepareforsubstantiveproblems.
1.2 Comments on Miles Chapter 1
MilesChapter1onComputersandProgramsmakesagoodintroductionandgivescontext. Readforthegroundingit
gives.
ThechaptermakessomereferencetoMicrosoft,theoriginalcreatorofC#,anditsVisualStudiosoftwaredevelopment
environment,whichworksonlyonWindowsmachines,andcostsalotifyouarenotastudent. Theoptionaltextby
Lewis discussed Visual Studio at some length. The next section of these notes will introduce an alternative to the
Microsoft environment: Mono, which is free, open-source software that makes C# available for multiple platforms:
Windows,Mac,orLinuxmachines.
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IntroductoryProgramminginC#,Release1.0
2 Chapter1. Context
CHAPTER
TWO
C# DATA AND OPERATIONS
2.1 Development Tools
2.1.1 About Software Development Kits (SDKs)
Asoftwaredevelopmentkit(SDK)isasetoftoolsfordevelopinginaparticularprogramminglanguage(inourclass,
C#).Developinginalanguagemeanseverythingfromcompilingtorunningand(whenthingsgowrong)todebugging
programs.
TheMicrosoftSDKistheproprietaryimplementationof.Net.ItrunsonlyonWindowsandistheprimarydevelopment
frameworkforallthingsMicrosoft.
TheMonoProjectSDK<http://mono-project.com>isthefree/opensourceequivalentimplementationoftheMicrosoft
SDK.Itrunsonallmajorplatforms(includingWindows)andisneededinsituationswhereyouwanttodevelop.Net
applicationsonnon-Windowsplatforms.
Asaninterestingaside,thecompanywhosedevelopersleadtheworkontheMonoSDKareworkingoncommercial
toolsthatallowyoutodevelop/runapplicationswrittenin.NetonAppleiOSandAndroidmobiledevices(phonesand
tablets).
2.1.2 About Integrated Development Environments (IDE)
Whilejustabouteverythingyouneedtocreateprogramscan,indeed,befoundintheSDK,itisnotlongbeforeyou
wishtherewerean“appforthat”sotospeak. Whilemostprogrammerswhodevelopedcode(likeyourinstructors)in
the1970s-1990slearnedtoprogramdirectlywiththeSDKusingthecommandline, today’sprogrammerslargelyto
preferworkinginanIDE.
TherearetwomajorIDEsfor.Netdevelopment,whichweexplainbrieflybelow:
• VisualStudioistheMicrosoftIDEthatinterfacesdirectlytotheMicrosoftSDK.
• MonoDevelopisthefree/opensourceIDEfordevelopingapplicationsusingtheMonoSDKonWindowsand
allotherplatforms(inparticular,LinuxandOSX).
Inaddition, thereisanotherWindows-specificIDE,SharpDevelop, thatinspiredthecreationofMonoDevelop. Itis
still actively maintained and provides a somewhat “lighter weight” alternative to Visual Studio for Windows users.
LikeMonoDevelop,itisaimedatdeveloperswhowouldpreferamorefree/opensource“friendly”version.
2.1.3 Our Approach
Intheinterestofprovidingaconsistentexperienceforourstudents,wewillbeusingMono(theSDK)andMonoDe-
velop (the IDE) for everything we demonstrate in class. We will also be encouraging you to use it for your work,
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IntroductoryProgramminginC#,Release1.0
especiallyifyouareinterestedinnon-Microsoftplatforms.
OurnotesassumeforthemostpartthatyouareworkingwithMonoandMonoDevelop. Inmostcases,whatweare
showingyouinMonoandMonoDevelopwilltranslatealmostasistotheMicrosoftequivalents. However,thereare
sometools,suchasthecsharpinterpreter,thathavearoughanaloginMicrosoft’stoolsbutinasomewhatlimited
form. AsthereissignificantevolutionofboththeMicrosoftandMonotoolchains–afancywordwewantyoutoknow
andamoreelegantwayofsayingSDK–we’llissueupdatestothesenotes.
2.1.4 Installing Mono
BecausetheMonoProjectwebpageisknowntochangefrequently,theseinstructionsaredesignedtobeasgenericas
possible. Ifyouhaveanyquestions,youshouldcontacttheinstructorsimmediatelyorseektutoringhelp.
2.1.5 OS X
1. Goto<http://mono-project.com>.
2. LookfortheMonodownloadslink. YouwanttogetthelateststableversionofMonoforOSX.Forthisclass,
youneedversion2.10orlater.
3. YoumayseealinktodownloadRuntimeorSDK.MakesureyouselectSDK.
4. ForOSX,theSDKisdistributedasaDMGdiskimage. You’llneedtodownloadthisimageanddouble-click
it. Opentheimageandruntheinstaller. Administrativeprivilegesarerequiredtoruntheinstaller,soifyoudo
notknowthisinformation,pleasestophere.
5. Onceinstallationiscompleted,youhaveeverythingneededtostartusingtheIDE,MonoDevelop.
6. Nowgoto<http://mono-develop.com>.
7. AswithMono,weneedtolookforthedownloadslink. Youshoulddownloadthestableversion.
8. AswithMono,youwillseeaDMGfile,whichyoushoulddownloadanddouble-clicktomountonyourdesktop.
9. Thistime,youwillseeanAppforMonoDevelop,whichyoucandraganddropintotheApplicationsfolder.
HereishowtodoaquicksanitycheckofyourMonosetup:
1. GotoApplications->UtilitiesandlaunchtheTerminalapplication.(Terminalishowyougettoacommand-line
shellinOSX.)
2. You’llseeapromptthatlookslikethiscomputername:folder user$.ThismeansthatTerminalisready
forinput.
3. Typewhich csharpandhitenter/return. Youshouldsee/usr/bin/csharpasoutput. csharpisthe
C#interpreter.
4. Type which dmcs and hit enter/return. You should see /usr/bin/dmcs as output. dmcs is one of the
interfacestotheC#compiler.
5. Ifthetwoprecedingstepsweresuccessful, youcanlaunchMonoDevelopbydouble-clickingtheiconinyour
Applicationsfolder. (Youwon’tknowwhattodowithityet,butatleastyoucanverifythatitlaunchescorrectly
andthenuseCommand-Qtoexit.)
2.1.6 Windows
1. Goto<http://mono-project.com>.
4 Chapter2. C#DataandOperations