programming in ANSI C-Chapter 6 Decision Making and Looping

.,Chapter6DecisionMakingandLooping,PROGRAMMINGINANSIC,.,Question,Questions:Howdowecalculatethesumfrom1to5?Howdowecalculatethesumfrom1to100?,main()intsum=0;sum=sum+1;sum=sum+2;sum=sum+3;sum=sum+4;sum=sum+5;printf(sum=%d,sum);,main()intsum=0;sum=sum+1;sum=sum+2;sum=sum+3;sum=sum+100;printf(sum=%d,sum);,Letsfindoutthelawofsuchquestion:,Wheni=1,2,3,100do:sum=sum+i;,Loopconstruct!,.,Flowchart,Inalooping,asequenceofstatementsisrepetitivelyexecuteduntilthelooptestconditioncantbesatisfied.Aloopstatementconsistsof2segments:TheloopcontrolstatementTheloopbody,.,Chapter6,Inthischapter,wewilllearn:whilestatementdo.whilestatementforstatementAssistedcontrolstatements:breakandcontinueLoopingconsistsofifandgoto,.,whileStatement,Theformofwhilestatement:while(testcondition)loopbody,Thetestconditionisevaluatedfirst,andifitistrue,theloopbodyisexecuted.,.,whileStatement,Programtocalculatethesumfrom1to100.,main()inti=1,sum=0;while(i=100)sum=sum+i;i+;printf(%d,sum);,Iftheloopbodyconsistsofmorethanonestatement,weshouldusecompoundstatement.,.,whileStatement,Programtocalculatethesumfrom1to100.,main()inti=1,sum=0;while(i=100)sum=sum+i;i+;printf(%d,sum);,infiniteloop,Wecanusectrl+breaktostoptheexecutionofprogram.,main()inti=1,sum=0;while(i=100)sum=sum+i;i+;printf(%d,sum);,.,whileStatement2Segments,.,whileStatement2Segments,Theloopbodycanbeanytypestatement.Theloopbodyshouldbeasinglestatementoracompoundstatement.Theloopbodymustcontainsomestatementsmakingthelooptendtoend.Avoidinfiniteloop.,.,do.whileStatement,Theformofdo.whilestatement:doloopbodywhile(testcondition);,Theloopbodyisexecutedfirst,andthenthetestconditionisevaluated.,Indo.whilestatement,theloopbodyisalwaysexecutedatleastonce.,.,do.whileStatement,do.whilestatementcanchangetowhilestatement:,.,do.whileStatement,do.whilestatementcanchangetowhilestatement:,doloopbodywhile(testcondition);,loopbodywhile(testcondition)loopbody,.,do.whileStatement,Programtocalculatethesumfrom1to100.,main()inti=1,sum=0;dosum=sum+i;i+;while(i=100);printf(%d,sum);,Likewhilestatement,iftheloopbodyconsistsofmorethanonestatement,weshouldusecompoundstatement.,.,do.whileStatement2Segments,Theloopbodycanbeanytypestatement.Theloopbodyshouldbeasinglestatementoracompoundstatement.Theloopbodymustcontainsomestatementsmakeingthelooptendtoend.Avoidinfiniteloop.,Payattentiontothissemicolon!,.,whilescanf(%d,main()inti,sum=0;scanf(%d,15050,15050,1010,101101,whilethetestconditionisevaluatedfirstdo.whiletheloopbodyisevaluatedfirstwhilethetimesofexecutionofloopbody0dowhilethetimesofexecutionofloopbody1,.,forStatement,Theformofforstatement:for(exp1;exp2;exp3)loopbody,exp1,exp2andexp3areanytypeexpressions,andtheyallcanbeomitted.Buttheseparatorsemicoloncantbeomitted.for(;)isequivalenttowhile(1)infiniteloopforstatementcanbechangedtowhilestatement,.,forStatement,Theformofforstatement:for(exp1;exp2;exp3)loopbodyThegeneralapplicationformofforstatement：for(initialization;testcondition;increment)loopbodye.g.for(sum=0,i=1;i=100;i+)sum=sum+i;,isequivalentto：sum=0;i=1;while(i=100)sum=sum+i;i+;,.,forStatement,Theformofforstatement:for(exp1;exp2;exp3)loopbodyexp1andexp3canbecommaexpression.e.g.for(sum=0,i=1;i=100;sum+=i,i+);,isequivalentto：sum=0;for(i=1;i=100;i+)sum+=i;,.,forStatement,Programtocalculatethesumfrom1to100.,main()inti,sum;sum=0;for(i=1;i=100;i+)sum=sum+i;printf(%d,sum);,i=1;for(;i=100;i+)sum=sum+i;,i=1;for(;i100)break;sum=sum+(i+);,breakStatement,Programtocalculatethesumfrom1to100.,.,continueStatement,Form:continue;Function:Skipthefollowingstatementsinthisloop,causingthetestconditionofthenextlooptobejudged.,Thecontinuecanonlybeusedinloops.,.,continueStatement,continue;,.,continueStatement,Outputthenumbers,between100and200,whichcantbedividedexactlyby3.,main()intn;for(n=100;n=200;n+)if(n%3=0)continue;printf(%5d,n);,.,LoopsProgram1,Outputtheformer40numbersoftheFibonaccisequence.Fibonaccisequence:1,1,2,3,5,8,13,21,34,F1=1(n=1)F2=1(n=2)Fn=Fn-1+Fn-2(n3),f1f2?,.,LoopsProgram1,main()longf1=1,f2=1;inti;for(i=1;i=20;i+)printf(%12ld%12ld,f1,f2);if(i%2=0)printf(n);f1=f1+f2;f2=f2+f1;,i=1;while(i=20)printf(%12ld%12ld,f1,f2);if(i%2=0)printf(n);f1=f1+f2;f2=f2+f1;i+;,i=1;doprintf(%12ld%12ld,f1,f2);if(i%2=0)printf(n);f1=f1+f2;f2=f2+f1;i+;while(i=20);,.,LoopsProgram2,Judgewhetheranintegerisaprimenumberornot.Makembedividedbyallthenumbersbetween2andthesquarerootofm.Ifmcanbedividedexactlybyacertainnumberinthose,misnotaprimenumber,otherwiseitis.,.,LoopsProgram2,#includemain()intm,i,k;scanf(%d,Ifmcanbedividedexactlybythenumberbetween2andsqrt(m),misnotaprimenumber,sotheloopwillbeterminatedbybreakstatement,andatthattime,imustbelessorequaltok.Otherwisemisaprimenumber,andafterthelastloop,iisequaltok+1.,.,LoopsProgram2,#includemain()intm,i,k;scanf(%d,doif(m%i=0)break;i+;while(i=k);,for(i=2;i=k;i+)if(m%i=0)printf(%disnotaprimenumber,m);break;elseif(i=k)printf(%disaprimenumber,m);,Cantjudge1,2,3!,.,LoopsProgram3,Outputalltheprimesbetween100and200.,#includemain()intm,i,k,n=0;for(m=101;mk)printf(%5d,m);n=n+1;if(n%10=0)printf(n);,Trytousewhileanddowhilestatementtorewritethisprogram.,.,LoopsProgram4,Readinapositiveinteger,andoutputitinreversedorder.Forexample:readin12345,output54321.,#includemain()intn;printf(Inputapositiveinteger:);scanf(%d,/*numberisdecreasedby10times*/,.,LoopsProgram5,Outputthemultiplicationtable.,irepresentstheline：（1i9）jrepresentsthecolumn：（1ji）,.,LoopsProgram5,main()inti,j;for(i=1;i10;i+)for(j=1;j=i;j+)printf(%d*%d=%dt,j,i,i*j);printf(n);,Trytouseothernestingofloopstorewritethisprogram.,.,LoopsProgram6,Readinintegern,andoutputnfactorial(n!).,main()intn;intm=1;printf(Pleaseinputanumber:);scanf(%d,Pleaseinputanumber:,5,printf(%d!=,n);,printf(%d,m);,0!=120,5!=120,Pleaseinputanumber:,8,8!=-25216,long,printf(%ld,m);,8!=40320,.,gotoStatement,Usedto:Jumpunconditionallyfromonepointtoanotherinaprogram.Generalforms:gotolabel;label:statement;orlabel:statement;gotolabel;,.,gotoStatement,Aboutlabel:Alabelmustbeavalididentifier,dontuseanintegerasalabel.Ala