说明学习物理chapterhcs

Maingotowhiledo-whileforNestingofComparisonofthebreakandcontinue casestudy（ExhaustivealgorithmandI tivealgorithm） Problem6.1What’sloo ？Whywouldweuse 6.1What’sloo ？Whywouldweuse WhenWhenpisWhenpisLoop while pre- while(test{bodyofthe} Flow shouldbe.whenconditionis.

Controlvariableshouldbeupdatedinthebodyloop. example，calculatevoidmain({intn=2;floatsum=1;while(n<=10){}

/*nisthecontrolvariable/*n++;updatethecontrolprintf("sum=%f\n",printf("sum=%f\n",} voidmain({intn=2;floatsum=1;while(n<=10){sum=sum*n;}}Infinite nothing

voidmain({intn=2;floatsum=1;while(n++<=10){}}≠ ExerciseinWriteacprogramtoprintoutalltheprimenumbersfrom2to200. do-whiledbodybodyofthe}while(testcondition) differentwithwhile，inthedo-whileconstruct,thebodyoftheloopisalwaysexecutedatleastonce.FlowWhenpis Ifthebodyoftheloopwilldointhefirsttimewithoutanycondition,usedo-while.endwithasemicolon(;).Soweendwithasemicolon(;).Sowecan“do-while”asonethelooptoTheremustexistastatementwhichtheloopto Calculate10！withdo-voidmain(floatsum=1;do{floatsum=1;do{}while(n<=10);printf("sum=%f\n",sum);} voidmain({inti=10;while(i<10);}

voidmain({intx=23;printf("%d\n",x--);}

voidmain({intx=3;printf("x=%d\n",x);}

voidmain({inti=1;while(i++<8);}}

Inputacharacterstringwhichends‘?’，counthowmanydigitsarein inputchprintcountif(ch>=’0’&&ch<=’9printcount voidmain(){intcount=0;charch;ch=getchar();while(ch!=’?’){if(ch>=’0’&&ch<=’9’)count++;ch=getchar();} while((ch=getchar())!=’?’)if(ch>=’0’&&ch<=’9’)count++; for{bodyoftheexpression1：initializing 达式orrepetition达式orrepetitionexpression3：controlvariableFlow}bodyofthe{bodyoftheCalculatevoidmain({intfloatn<=100{intfloatn<=100is} expression1,expression2andexpression3can expression1,expression2andexpression3canomitted,but“;”should。Itmeansnobodyofloopwhenfor(;;)endwith“;”floatfloatfor(sum=1,n=2;n<=100;sum*=n,; intn＝2;floatsum=1;for(;n<=100;)intn＝2;floatsum=1;for(;;)elsebreak;

式1、式2、式3都可省， Input50digitsof0～9，counthowmanyevens,oddsandzerosare, Theyareacceptedbynumericalcharacters,notnumbers.characteristransferredintowholenumber.Wecancharacteristransferredintowholenumber. voidmain({inti,n_even=0,n_odd=0,n_zero=0;charnum;for(i=1;i<=50;i++)scanf("%c",&num);num=num-’0’；if(num!=0&&num%2==0)n_even++;if(num%2!=0)n_odd++;if(num==0)}printf("Thereare%2devens,%2dodds,%2dzeros",n_even,n_odd,n_zero);}

thereare9evens,8zeros,19nestingofOneloopstatementwithinanotherloopUsingwhile、do-whileandforcanbeincludedeachUsing while(while(}while(

for(;;for(;;}while(while();} for(;;while({……}{…for(;;}while( Nestingof2x1=23x1=33x2=64x1=42x1=23x1=33x2=64x1=44x2=84x3=125x1=55x2=105x3=155x4=206x1=66x2=126x3=186x4=246x5=307x1=77x2=147x3=217x4=287x5=357x6=429x1=99x2=189x3=279x4=369x5=459x6=549x7=639x8=729x1=99x2=189x3=279x4=369x5=459x6=549x7=639x8=72 S1：S1：for(i=1;i<=9;{printtheithrowS1.1：for(j=1;j<=i;

Nestingof{printthejthcolumnS1.1.1：printi*jontheithrowandjthcolumnprintf("%d*%d=%d",i,j,i*j); Nestingofvoidmain({for(i=1;i<10;i++)for(i=1;i<10;i++)for(j=1;j<=i;j++)printf("%dx%d=%d",i,j,i*j);}}} Nestingof while(i<=8)for(k=1;k<=8-for(j=1;j<=(2*i-}}

voidmain({inti,j,k;while(i<=8)forfor(j=1;j<=(2*i-}} ifand breakandbreakWhenabreakstatementisencounteredinsidealoop,theloopisimmediayexitedandtheprogramcontinueswiththestatementimmediayfollowingtheloop.Inthecaseofnestingloop,breakonlyterminatesthecurrentloop. continuecontinuewillgoto“while”totesttheThecaseloop，continuewillgotoexpression3,thentestexpression2toSkipthefollowingstatementsandcontinuewiththenext whetheranotherloopwill nwhiley

whileyif(exp2)

if(exp2)

statements statements Writeaprogramtocomputes=1+1/2+1/3+…+1/n+… voidmain({longfloatmax,s=0.0;scanf("%f",&max);for(n=1;;n++){

/*usebreakto}printf("s=%f,n=%d\n",s,}

s=10.000051, inputExpression2isinputExpression2isalways Breakwillprints,for(n=1;;n++){ }printf("%f,%d\n",s, 6.96.9case Testallcases(orstates)untiloneormuchmoresolutionsisgot.Controlledloopexactlyhowmanytimestheloopexactlyhowmanytimestheloopwillbeexecuted。Sentinel-controlledloops：thenumberofrepetitionsisnotknownbeforetheloop Movebricksmoves4bricksonetime，3perwomanonetimeand1brickfortwochildsonetime.Nowmoves4bricksonetime，3perwomanonetimeand1brickfortwochildsonetime.Nowrequireallthebricksaremovedinonetime，howmanymanandwomenandchildsareneeded?Wecan S1：because0<=men<9，wecanS1：because0<=men<9，wecangetwomenchild}while(while(women<12{findout} S3：child=36－men－womencondition： {intmen,women,child;for(men=0;men<9;men++){intmen,women,child;for(men=0;men<9;men++)for(women=0;women<12;women++){if(child%2==0&&}} voidmain({intmen,women,if(child%2==0&&}}}} tive tionistouseanewvaluetore theoldoneorusetheoldvaluetodeduceanewonewithrecursivemethodTwo Exacti tion：Theexactsolutionwillbe gotafterseverali Approximatei tion：Onlytheapproximatesolutionisgotafterseveral tion.Itcan’tfindexactsolution,butcanapproachtoit.Useaccuracytocontroltherepetitiontimes. Thereare1.4billionpeoplenow.Howmuchisitafter10yearsiftheannualgrowthrateis2％.Supposethepresentpeopleism，1yearlater,itwillbe：m=m*(1+2%)，Wecanget10yearslater’snumberbyexecuting10timesm=m*(1+2%)。initial tive tivetimes：for(i=1;i<11;i++)m=m*(1.+2./100.);

Example2，Printoutthefirst40itemsoftheFibonacciseries. Suchas:Initialvalue：fib1=1; tive tivetimes：40-

Initialvalue：fib1=1; tiveformula tivetimesvoidmain({intlongfib,fib1=1,

voidmain({intprintf("%ld%ld",fib1,fib2);longfib1=1,for(m=3;m<=40;m++){printf("%12ld",fib);}}

for(m=1;m<=20;m++)printf("%12ld%12ld",fib1,fib2);if(m%2==0)printf("\n");}} InitialExample3，useInitial tiveErroris=1.0E-6,whichdecidestheconditionif tionwillcontinue.while(fabs(term)>),i onceagain. Example4，Howtosolveasimplenonlinearequationf(x)=0。Rewritethenonlinearequationf(x)=0asthei Giveafittingvaluex0，itcancreateaseries：x0,x1,x2,…,xn,…Iftheseriesconverge(i.e.thereexistsalimitation.)，andthefunctioniscontinuousinthesolutioninterval,then,thelimitvalueistheapproximatesolutionoff(x)=0. Typic