CS 115 Exam 2 Review Quiz

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1 CS115Exam2ReviewQuiz Oct.28,2009 Rules Youmustbrieflyexplainyouranswerstoreceivepartialcredit. Whenasnippetofcodeisgiventoyou,youcanassume o thatthecodeisenclosedwithinsomefunction,evenifnofunction definitionisshown o thatthemainfunctionisproperlydefined o thattheiostream,algorithm,fstream,iomanip,string,and cmathlibrarieshavebeenincludedatthebeginningoftheprogram. Whenyouareaskedtowriteasnippetofcode,youmayassume o thatyourcodeisenclosedwithinsomefunction o thatanynecessarylibrarieshavebeenincluded. Whenyouareaskedtowriteacompleteprogram,youmustwritethe #includestatements,theint main(),etc.inyoursolutiontoreceivefull credit. Alineconsistingsolelyof representsoneormoreunspecifiedc++ statements,someofwhichmaychangethevaluesofprogramvariables. Youareencouragedtousethebacksofthesepagesforscratchpaper.Ifyou wantanswerswrittentheretobegraded,theymustbeveryclearlylabeled andalsonotedonthemaintest,e.g. Seethebackofpage1for3a.

2 Problem1:25points. (a) Whatdoesthissnippetofcodeprint? for (int i = 1; i < 3; i++) { for (int j = 1; j <= 2; j++) { cout << i+j << " "; cout << endl; (b) Whatdoesthissnippetofcodeprint? int a[6] = {5, 8, 7, 9, 13, -1; cout << a[4] << endl; (c) Ifthefollowingfunctionisdefinedsomewhereintheprogramand prototypedabovemain. int square(int& x) { return x*x; whatdoesthefollowingcodeprint? int x = 5; int y = square(x); cout << x << endl; cout << y << endl;

3 (d) Forthesnippetofcode float f[50]; whatisthedatatypeoff[15]? (e) Ifthefollowingfunctionisdefinedsomewhereintheprogramand prototypedabovemain. int my_function (int x, float array[]) { array[1] = 2.5; return x*2; whatdoesthefollowingcodeprint? int x = 5; float a[3] = {0.2, 0.4, 0.6; int y = my_function(x, a); cout << x << endl; cout << y << endl; cout << a[1] << endl; cout << a[2] << endl;

4 Problem2:25points. Thesnippetsofcodeinthisproblemdonotsuccessfullyaccomplishthetask describedintheiraccompanyingcomment.correctthecodesothatitperformsthe taskdescribedinthecomment.thecodemayhavemorethanoneerror.make yourcorrectionsclearandunambiguous. (a) /* Function that finds and returns the smallest element of an integer array. Inputs are the array and its size */ int FindMin(int[] array, int size) { int min = 0; for (int i=0; i <= size; i++) { if (i < min) { min = array[i]; (b) Assumethatthe2Darray int x[100][5] hasalreadybeendeclaredanddefined. /* Prints out all the elements of the 2D array X */ for (int i=0; i<=5; i++) { cout X[i][j];

5 (c) /* Function sets every element of the array arr to init_value. Size = size of the array. */ int InitArray(int[] arr, int init_value, int size) { for (int i=0; i<= size; i+1) { cout << init_value;

6 Problem3:25points. Writeshortsnippetsofcodetoaccomplishthefollowingtasks: (a) Foranarraythathasbeendeclaredas float floatarr[5][8]; writeasnippetofcodethatcomputesandprintstheaverageofallthe elementsintheentirearray. (b) Writeasnippetofcodethatrepeatedlyasksfortheuser sinputasa character.iftheuser sinputis u,yourcodeshouldcallthefunction Update(),whichhasnoinputs.Iftheuser sinputis p,yourcodeshould callthefunctionprint(),whichhasnoinputs.iftheuser sinputis q, youshouldprintagoodbyemessageandstopprintingthemenu.iftheinput isanythingelse,youshouldprintanerrormessageandreprintthemenu.

7 (c) WriteafunctioncalledGetLargestOddwiththefollowingproperties: a. Parameters: i. a,anarrayofintegers ii. N,aninteger(thesizeofthearray) b. Returnvalue:anint c. Description: i. Goesthroughthearrayinsequence,fromthefirstelementto thelast ii. Returnsthelargestoddelementofthearray,ignoringelements thatareevennumbers iii. Ifthearraydoesn thaveanyoddelements,returns0

8 Problem4:25points. Forthisproblem,youmustwriteacompleteprogramthatcontainsthefollowing: Afunction,definedbelowthemainfunction,calledGetIntegerswiththe followingproperties: o Parameters: inputarr,anarrayofintegers N,aninteger(thesizeofthearray) o Returnvalue:abool o Description: Promptstheusertoenter1000integers. Promptsforeachintegerindividually Returnsfalseimmediatelyiftheuserentersaninvalid integer Returnstrueifalloftheintegerswerefilledincorrectly PrototypeforGetIntegers Afunction,definedbelowthemainfunction,calledAllEqualwiththe followingproperties: o Parameters: inputarr,anarrayofintegers N,aninteger(thesizeofthearray) o Returnvalue:Thefunctionshouldreturnaboolwhosevalueistrue ifalloftheelementsofthearrayareequalandfalseotherwise. PrototypeforAllEqual Amainfunctionthatdoesthefollowing: o Declaresanarrayof1000integers o CallsGetIntegerstoinitializethearray o Iftheuserenteredaninvalidinteger,printsanerrormessageand exits o Otherwise,callsAllEqual.BasedontheresultofAllEqual,prints Allelements=[num] ifalloftheelementsareequal,where[num]is thenumberthattheyareallequalto.

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