CS 115 Final Exam, Spring 2009

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1 CS115FinalExam,Spring2009 Yourname: Rules ReferencematerialontheSTLclassesandalgorithms,aswellasfunctions thatoperateonc strings,isincludedattheendofthisdocument. Youmustbrieflyexplainyouranswerstoreceivepartialcredit. Whenasnippetofcodeisgiventoyou,youcanassumethatthecodeis enclosedwithinsomefunction,evenifnofunctiondefinitionisshown.you canalsoassumethatthemainfunctionisproperlydefinedandthatthe iostream,fstream,iomanip,vector,algorithm,string,cstring, andcmathlibrarieshavebeenincludedatthebeginningoftheprogram. Whenyouareaskedtowriteasnippetofcode,youmayalsoassumethatitis enclosedwithinsomefunctionthatanynecessarylibrarieshavebeen included. Whenyouareaskedtowriteacompleteprogram,youmustwritethe #includestatements,theint main(),etc.inyoursolutionforfullcredit. Alineconsistingsolelyof representsoneormoreunspecifiedc++ statements,someofwhichmaychangethevaluesofprogramvariables. Grade(instructoruseonly) Score Max Problem1 15 Problem2 15 Problem3 15 Problem4 15 Problem5 20 Problem6 20 Total 100

2 Problem1:15points. Matchthefollowingdescriptionswiththetermtheydescribebywritingthattermin thespaceprovided.thechoicesoftermsare: this constructor destructor class private public object pointer STL dereference passbyreference passbyvalue Notalltermswillbeused. (a) (b) (c) (d) (e) Termforamemberofaclassthatcannotbeaccessedfromoutsidethe class Afunctionthatisautomaticallycalledwhenanobjectiscreated Awayofallowingafunctiontomodifyitsinputarguments Aprogrammer definedc++datatypethatcancontainitsownvariables, functions,andoperators Theoperationoffollowingapointertothethingitpointsto(i.e.the operation*(ptr))

3 Problem2:15points. Using the selection sort code on the next page, which works identically to the code from your labs, show the contents of the following 5-element array after each iteration of SelectionSort s loop in the labeled boxes. Leave the boxes blank if the loop does not complete a given iteration. INITIAL VALUE AFTER i=0 AFTER i=1 AFTER i=2 AFTER i=3 AFTER i=4 AFTER i=5 AFTER i=6

4 CodeforProblem2. Youmaytearthispageoutofyourexam. void SelectionSort(int arr[], int size) { int min_pos = 0; // This is the loop in question for (int i = 0; i < size-1; i++) { min_pos = FindMinPos(arr, i, size); if (min_pos!= i) { swap ( arr[i], arr[min_pos] ); int FindMinPos(int arr[], int size) { int minval = arr[0]; int minpos = 0; for (int i = 1; i < size; i++) { if (arr[i] < minval) { minval = arr[i]; minpos = i; return minpos; void Swap (int& a, int& b) { int temp = a; a = b; b = temp;

5 Problem3:15points. Completethedefinitionsofthefollowingfunctionsasindicatedbytheircomments. Youmayassumethatanynecessarylibrarieshavebeenincluded. Hint:Eachfunctioncanbewrittenintwolinesofcodeorfewer,noneofwhichare cinorcoutstatements. (A) /* Sort the input vector and return the value of its smallest element. */ int Funct1 (vector<int>& s) { (B) /* Return the sum of the lengths of the two input C-strings. */ int Funct2 (char* a, char* b) {

6 (C)Forthispart,assumethattheclassRectanglehasprivatefields int length; int width; Youwillbewritingthe>operator. Foryourreference,thecopyconstructorfortheclassisgivenbelow: /* Copy constructor for Rectangles. */ Rectangle::Rectangle (const Rectangle& other) { this->length = other.length; this->width = other.width; /* Overloaded > operator for the Rectangle class. Returns TRUE if the area of this is greater than the area of other and FALSE otherwise. You fill this in. */ bool Rectangle::operator > (const Rectangle& other) const{

7 Problem4:15points. Forthisproblem,youmustwriteaclassdefinitionforaclassnamedRT(asin righttriangle )thatcontainsthefollowing: Notethatdatamembersshouldbeprivateandmemberfunctionsshouldbepublic. Variablesforthethreesidesofthetriangle(asdouble variablesnameds1, s2,andhypo) Prototypeforadefaultconstructor PrototypeforafunctioncalledSetSides.Thisfunctionwilltaketwo variablesoftypedoubleasinputsandwillreturnabool. PrototypeforafunctioncalledGetHypo.Thisfunctionwillreturnthelength ofthetriangle shypotenuse. PrototypeforafunctioncalledGetArea.Thisfunctionwillreturnthearea ofthetriangle.

8 Problem5:20points. Inthisproblem,youwillwritedefinitionsforthefunctionsintheclassRT.Hereisa littlebitmoreinformationaboutthefunctions.youmayassumethat<cmath>is included.notethatnoneofyourcodeforthisproblemshouldincludecinorcout statements! Thedefaultconstructorwillinitializethethreesidelengthsto0. TheSetSidesfunctionwillworkasfollows: o Ifoneorbothoftheinputsislessthanzero,itwillreturnfalse. o Otherwise: Itwillsets1equaltothefirstinput. Itwills2equaltothesecondinput. Itwillsethypoequaltothesquarerootof(s1 2 +s2 2 ).Thenit willreturntrue. TheGetHypofunctionwillreturnthelengthofthehypotenuse. TheGetAreafunctionwillreturntheareaofthetriangle,whichishalfofthe productofs1ands2.

9 Problem6:20points. AssumethattheclassdefinitionyouwroteinProblems4and5arelocatedinafile calledrt.hinthesamedirectoryastheprogramyou reabouttowrite. WriteacompleteprogramthatusestheRTclassfromrt.htodothefollowing: CreateoneRTobjectwiththelengthsofthetwoshortersidessetto3and4. CreateanotherRTobjectandasktheusertosupplythelengthsofthetwo shortersides. UsingRT smemberfunctions: o Printthehypotenuseoftheuser striangle. o Print Theareasareequal iftheareasofthetwotrianglesareequal.

10 REFERENCE C stringfunctions: strlen InputisaC string.returnsthelengthofthestring(notincludingthe nullterminator). Usageexample:length = strlen(name); strcat InputistwoC strings.appendsthesecondstringtotheendofthefirst string(thefirststringischanged,butthesecondisnot). Usageexample:strcat(str1, str2); strcpy InputistwoC strings.copiesthesecondstringtothefirststring, overwritingtheoriginalcontents. Usageexample:strcpy(str1, str2); strcmp InputistwoC strings.returns0iftheyarethesame,anegativenumber ifstr2isalphabeticallygreaterthanstr1,andapositivenumberif str1isgreaterthanstr2. Usageexample:if(strcmp(str1, str2) > 0) Vectormemberfunctions: begin() Returnsaniteratortothevector sfirstelement clear() Removesallelementsfromthevector empty() Returnsaboolwhichistrueifthevectorisempty(haszero elements)andfalseotherwise end() Returnsaniteratorpointingjustpastthevector slast element pop_back() Removesthelastelementfromthevector push_back(value) Insertsvalueasanewelementattheendofthevector size() Returnsthenumberofelementsinthevector STLalgorithms(NOTmemberfunctions) Hereiter1anditer2areiteratorspointingtoelementsofanSTLclasssuchas vector. binary_search(iter1, Returnstrueifvalueisfoundintherange iter2, value) betweeniter1anditer2,falseotherwise count(iter1, iter2, Returnsthenumberoftimesvalueappearsinthe value) rangebetweeniter1anditer2 reverse(iter1, iter2) Reversestheorderoftheelementsbetweeniter1 anditer2 random_shuffle(iter1, Randomlychangestheorderoftheelements iter2) betweeniter1anditer2 sort(iter1, iter2) Sortstheelementsintherangebetweeniter1and iter2inascendingorder

CS 115 Final Review Quiz

CS 115 Final Review Quiz CS115FinalReviewQuiz December11,2008 Rules ReferencematerialontheSTLclassesandalgorithms,aswellasfunctions thatoperateonc strings,isincludedattheendofthisdocument. Youmustbrieflyexplainyouranswerstoreceivepartialcredit.