sicp

【SICP练习】150 练习4.6

练习4-6原文Exercise4.6.Letexpressionsarederivedexpressions,because(let(()…()))isequivalentto((lambda(…)))Implementasyntactictransformationlet->combinationthatreducesevaluatingletexpressionstoevaluatingcom
NoMasp·2015-04-01 08:00

【SICP练习】149 练习4.5

练习4-5原文Exercise4.5.Schemeallowsanadditionalsyntaxforcondclauses,(=>).Ifevaluatestoatruevalue,thenisevaluated.Itsvaluemustbeaprocedureofoneargument;thisprocedureistheninvokedonthevalueofthe,andtheresul
NoMasp·2015-03-31 17:00

【SICP练习】148 练习4.4

练习4-4原文Exercise4.4.Recallthedefinitionsofthespecialformsandandorfromchapter1:●and:Theexpressionsareevaluatedfromlefttoright.Ifanyexpressionevaluatestofalse,falseisreturned;anyremainingexpressionsareno
NoMasp·2015-03-31 13:00

【SICP练习】147 练习4.3

练习4-3原文Exercise4.3.Rewriteevalsothatthedispatchisdoneindata-directedstyle.Comparethiswiththedatadirecteddifferentiationprocedureofexercise2.73.(Youmayusethecarofacompoundexpressionasthetypeoftheexpres
NoMasp·2015-03-29 19:00

【SICP练习】146 练习4.2

练习4-2原文Exercise4.2.LouisReasonerplanstoreorderthecondclausesinevalsothattheclauseforprocedureapplicationsappearsbeforetheclauseforassignments.Hearguesthatthiswillmaketheinterpretermoreefficient:Sincep
NoMasp·2015-03-29 19:00

【SICP练习】145 练习4.1

练习4-1原文Exercise4.1.Noticethatwecannottellwhetherthemetacircularevaluatorevaluatesoperandsfromlefttorightorfromrighttoleft.ItsevaluationorderisinheritedfromtheunderlyingLisp:Iftheargumentstoconsinlist-
NoMasp·2015-03-29 16:00

【SICP练习】144 练习3.82

练习3-82原文Exercise3.82.Redoexercise3.5onMonteCarlointegrationintermsofstreams.Thestreamversionofestimate-integralwillnothaveanargumenttellinghowmanytrialstoperform.Instead,itwillproduceastreamofestimate
NoMasp·2015-03-29 15:00

【SICP练习】143 练习3.81

练习3-81原文Exercise3.81.Exercise3.6discussedgeneralizingtherandom-numbergeneratortoallowonetoresettherandom-numbersequencesoastoproducerepeatablesequencesof“random”numbers.Produceastreamformulationofthis
NoMasp·2015-03-29 15:00

【SICP练习】142 练习3.77

练习3-77原文Exercise3.77.Theintegralprocedureusedabovewasanalogoustothe“implicit”definitionoftheinfinitestreamofintegersinsection3.5.2.Alternatively,wecangiveadefinitionofintegralthatismorelikeintegers-st
NoMasp·2015-03-29 11:00

【SICP练习】141 练习3.72

练习3-72原文Exercise3.72.Inasimilarwaytoexercise3.71generateastreamofallnumbersthatcanbewrittenasthesumoftwosquaresinthreedifferentways(showinghowtheycanbesowritten).代码(define(squarex)(*xx)) (define(sum-s
NoMasp·2015-03-29 11:00

【SICP练习】140 练习3.71

练习3-71原文代码(define(Ramanujans)(define(stream-cadrs)(stream-car(stream-cdrs)))(define(stream-cddrs)(stream-cdr(stream-cdrs)))(let((scar(stream-cars))(scadr(stream-cadrs)))(if(=(sum-triplescar)(sum-tripl
NoMasp·2015-03-29 11:00

【SICP练习】139 练习3.70

练习3-70原文代码(define(merge-weighteds1s2weight)(cond((stream-null?s1)s2)((stream-null?s2)s1)(else(let((cars1(stream-cars1))(cars2(stream-cars2)))(cond((<(weightcars1)(weightcars2))(cons-streamcars1(merge-
NoMasp·2015-03-29 10:00

【SICP练习】138 练习3.69

练习3-69原文代码 (define(triplesstu)(cons-stream(list(stream-cars)(stream-cart)(stream-caru))(interleave(stream-map(lambda(x)(cons(stream-cars)x))(stream-cdr(pairstu)))(triples(stream-cdrs)(stream-cdrt)(str
NoMasp·2015-03-29 10:00

【SICP练习】137 练习3.68

练习3-68原文Exercise3.68.LouisReasonerthinksthatbuildingastreamofpairsfromthreepartsisunnecessarilycomplicated.Insteadofseparatingthepair(S0,T0)fromtherestofthepairsinthefirstrow,heproposestoworkwiththewh
NoMasp·2015-03-29 10:00

【SICP练习】136 练习3.67

练习3-67原文Exercise3.67.Modifythepairsproceduresothat(pairsintegersintegers)willproducethestreamofallpairsofintegers(i,j)(withouttheconditioni
NoMasp·2015-03-29 10:00

【SICP练习】135 练习3.66

练习3-66原文Exercise3.66.Examinethestream(pairsintegersintegers).Canyoumakeanygeneralcommentsabouttheorderinwhichthepairsareplacedintothestream?Forexample,abouthowmanypairsprecedethepair(1,100)?thepair(99
NoMasp·2015-03-29 10:00

【SICP练习】134 练习3.65

练习3-65原文Exercise3.65.Usetheseriesln2=1-1/2+1/3-1/4+……tocomputethreesequencesofapproximationstothenaturallogarithmof2,inthesamewaywedidabovefor.Howrapidlydothesesequencesconverge?代码(define(ln2-summands
NoMasp·2015-03-28 23:00

【SICP练习】133 练习3.64

练习3-64原文Exercise3.64.Writeaprocedurestream-limitthattakesasargumentsastreamandanumber(thetolerance).Itshouldexaminethestreamuntilitfindstwosuccessiveelementsthatdifferinabsolutevaluebylessthanthetoler
NoMasp·2015-03-28 23:00

【SICP练习】132 练习3.63

练习3-63原文Exercise3.63.LouisReasoneraskswhythesqrt-streamprocedurewasnotwritteninthefollowingmorestraightforwardway,withoutthelocalvariableguesses:(define(sqrt-streamx)(cons-stream1.0(stream-map(lambda(
NoMasp·2015-03-28 23:00

【SICP练习】131 练习3.62

练习3-62原文Exercise3.62.Usetheresultsofexercises3.60and3.61todefineaprocedurediv-seriesthatdividestwopowerseries.Div-seriesshouldworkforanytwoseries,providedthatthedenominatorseriesbeginswithanonzerocons
NoMasp·2015-03-28 22:00

【SICP练习】130 练习3.61

练习3-61原文代码(define(reciprocal-seriess)(cons-stream1(scale-stream(mul-series(stream-cdrs)(reciprocal-seriess))-1)))感谢访问，希望对您有所帮助。欢迎关注或收藏、评论或点赞。为使本文得到斧正和提问，转载请注明出处：http://blog.csdn.net/nomasp
NoMasp·2015-03-28 22:00

【SICP练习】129 练习3.60

练习3-60原文Exercise3.60.Withpowerseriesrepresentedasstreamsofcoefficientsasinexercise3.59,addingseriesisimplementedbyadd-streams.Completethedefinitionofthefollowingprocedureformultiplyingseries:(define(m
NoMasp·2015-03-28 22:00

【SICP练习】128 练习3.59

练习3-59原文代码a)(define(integrate-seriess)(stream-map*(stream-map/onesintegers)s))b)(definesine-series(cons-stream0(integrate-seriescosine-series))) (definecosine-series(cons-stream1(integrate-series(scal
NoMasp·2015-03-28 22:00

【SICP练习】127 练习3.58

练习3-58原文Exercise3.58.Giveaninterpretationofthestreamcomputedbythefollowingprocedure:(define(expandnumdenradix)(cons-stream(quotient(*numradix)den)(expand(remainder(*numradix)den)denradix)))(Quotientis
NoMasp·2015-03-28 22:00

【SICP练习】126 练习3.57

练习3-57原文Exercise3.57.HowmanyadditionsareperformedwhenwecomputethenthFibonaccinumberusingthedefinitionoffibsbasedontheadd-streamsprocedure?Showthatthenumberofadditionswouldbeexponentiallygreaterifwehad
NoMasp·2015-03-28 22:00

【SICP练习】125 练习3.56

练习3-56原文Exercise3.56.Afamousproblem,firstraisedbyR.Hamming,istoenumerate,inascendingorderwithnorepetitions,allpositiveintegerswithnoprimefactorsotherthan2,3,or5.Oneobviouswaytodothisistosimplytesteach
NoMasp·2015-03-28 22:00

【SICP练习】124 练习3.55

练习3-55原文Exercise3.55.Defineaprocedurepartial-sumsthattakesasargumentastreamSandreturnsthestreamwhoseelementsareS0,S0+S1,S0+S1+S2,….Forexample,(partial-sumsintegers)shouldbethestream1,3,6,10,15,….代码(de
NoMasp·2015-03-28 22:00

【SICP练习】123 练习3.54

练习3-54原文Exercise3.54.Defineaproceduremul-streams,analogoustoadd-streams,thatproducestheelementwiseproductofitstwoinputstreams.Usethistogetherwiththestreamofintegerstocompletethefollowingdefinitionofth
NoMasp·2015-03-28 22:00

【SICP练习】122 练习3.53

练习3-53原文Exercise3.53.Withoutrunningtheprogram,describetheelementsofthestreamdefinedby(defines(cons-stream1(add-streamsss)))分析s是一串2的幂。也就是1、2、4、8、16、32……
NoMasp·2015-03-28 22:00

【SICP练习】121 练习3.52

练习3-52原文Exercise3.52.Considerthesequenceofexpressions(definesum0) (define(accumx)(set!sum(+xsum))sum) (defineseq(stream-mapaccum(stream-enumerate-interval120))) (definey(stream-filtereven?seq)) (def
NoMasp·2015-03-28 21:00

【SICP练习】120 练习3.51

练习3-51原文Exercise3.51.Inordertotakeacloserlookatdelayedevaluation,wewillusethefollowingprocedure,whichsimplyreturnsitsargumentafterprintingit:(define(showx)(display-linex)x)Whatdoestheinterpreterprinti
NoMasp·2015-03-28 21:00

【SICP练习】119 练习3.50

练习3-50原文Exercise3.50.Completethefollowingdefinition,whichgeneralizesstream-maptoallowproceduresthattakemultiplearguments,analogoustomapinsection2.2.3,footnote12.(define(stream-mapproc.argstreams)(if((
NoMasp·2015-03-28 21:00

【SICP归纳】6 副作用与环境模型

虽说叫做副作用显得不太好听，但在Lisp中副作用还是非常重要的。而相对于所有状态都必须显式地操作和传递额外参数的方式，如果引进赋值和将状态隐藏在局部变量中，那么就可以用更加模块化的方式来构造系统。正如你所知道的，不用任何赋值的程序设计称为函数式程序设计。相反，广泛采用赋值的程序设计称为命令式程序设计。在C等命令式程序设计语言中，我们往往都要仔细考虑变量赋值的顺序，尤其是在循环中，但在函数式程序设计
NoMasp·2015-03-28 10:00

【SICP练习】118 练习3.45【待完成】

练习3-45原文Exercise3.45.LouisReasonerthinksourbank-accountsystemisunnecessarilycomplexanderror-pronenowthatdepositsandwithdrawalsaren’tautomaticallyserialized.Hesuggeststhatmake-accountand-serializershou
NoMasp·2015-03-26 20:00

【SICP练习】117 练习3.44

练习3-44原文Exercise3.44.Considertheproblemoftransferringanamountfromoneaccounttoanother.BenBitdiddleclaimsthatthiscanbeaccomplishedwiththefollowingprocedure,eveniftherearemultiplepeopleconcurrentlytransf
NoMasp·2015-03-26 19:00

【SICP练习】116 练习3.42

练习3-42原文Exercise3.42.BenBitdiddlesuggeststhatit’sawasteoftimetocreateanewserializedprocedureinresponsetoeverywithdrawanddepositmessage.Hesaysthatmake-accountcouldbechangedsothatthecallstoprotectedared
NoMasp·2015-03-26 19:00

【SICP练习】115 练习3.41

练习3-41原文Exercise3.41.BenBitdiddleworriesthatitwouldbebettertoimplementthebankaccountasfollows(wherethecommentedlinehasbeenchanged):(define(make-accountbalance)(define(withdrawamount)(if(>=balanceamoun
NoMasp·2015-03-26 19:00

【SICP练习】114 练习3.38-3.39

练习3-38原文Exercise3.38.SupposethatPeter,Paul,andMaryshareajointbankaccountthatinitiallycontains100.Concurrently,Peterdeposits10,Paulwithdraws20,andMarywithdrawshalfthemoneyintheaccount,byexecutingthefol
NoMasp·2015-03-26 14:00

【SICP练习】113 练习3.33

练习3-33原文Exercise3.33.Usingprimitivemultiplier,adder,andconstantconstraints,defineaprocedureaveragerthattakesthreeconnectorsa,b,andcasinputsandestablishestheconstraintthatthevalueofcistheaverageoftheva
NoMasp·2015-03-26 12:00

【SICP练习】112 练习3.28

练习3-28原文Exercise3.28.Defineanor-gateasaprimitivefunctionbox.Youror-gateconstructorshouldbesimilartoand-gate.代码(define(or-gateinput-1input-2output)(define(or-action-procedure)(let((new-value(logical-or
NoMasp·2015-03-26 12:00

【SICP练习】111 练习3.24

练习3-24原文Exercise3.24.Inthetableimplementationsabove,thekeysaretestedforequalityusingequal?(calledbyassoc).Thisisnotalwaystheappropriatetest.Forinstance,wemighthaveatablewithnumerickeysinwhichwedon’tne
NoMasp·2015-03-26 12:00

【SICP练习】110 练习3.23

练习3-23原文Exercise3.23.Adeque(“double-endedqueue”)isasequenceinwhichitemscanbeinsertedanddeletedateitherthefrontortherear.Operationsondequesaretheconstructormake-deque,thepredicateempty-deque?,selectors
NoMasp·2015-03-26 11:00

scheme中if作为特殊形式而不是普通过程的原

SICP的练习1.6中试图将scheme中的if写成cond的形式：C++(define(new-ifpredicatethen-clauseelse-clause)(cond(predicatethen-clause
ahxxx2·2015-03-26 11:13

【SICP练习】109 练习3.22

练习3-22原文Exercise3.22.Insteadofrepresentingaqueueasapairofpointers,wecanbuildaqueueasaprocedurewithlocalstate.Thelocalstatewillconsistofpointerstothebeginningandtheendofanordinarylist.Thus,themake-queu
NoMasp·2015-03-25 11:00

【SICP练习】108 练习3.21

练习3-21原文Exercise3.21.BenBitdiddledecidestotestthequeueimplementationdescribedabove.HetypesintheprocedurestotheLispinterpreterandproceedstotrythemout:(defineq1(make-queue)) (insert-queue!q1'a) ((a)a)
NoMasp·2015-03-25 11:00

【SICP练习】107 练习3.8

练习3-8原文Exercise3.8.Whenwedefinedtheevaluationmodelinsection1.1.3,wesaidthatthefirststepinevaluatinganexpressionistoevaluateitssubexpressions.Butweneverspecifiedtheorderinwhichthesubexpressionsshouldbe
NoMasp·2015-03-25 10:00

【SICP归纳】5 泛型运算符

关于数据抽象，有两个很重要的思想。一是在构建一些水平的抽象障碍在这个系统中。用某些对象来代换这些单独使用的抽象屏障。二是当需要使用某种形式的数据对象时，往往可以由其他人来将其实现，而我们并不需要知道具体操作。这都是在数据抽象方面非常强大的编程方法。但是这还不足以完成一个真正复杂的系统。在这里的问题出在“其他人”，作者常举的例子是Georges。归结来说，有很多人都工作在这个系统上，但所有的这些设计
NoMasp·2015-03-23 20:00

【SICP归纳】4 模式匹配和以规则为基础的代换

在书中符号数据一节中，作者写了关于微积分的演算规则的程序。这是一个很程序化的程序，我们所做的是在讲这些（数学）规则翻译成计算机语言。因为它有程序化的行为和结构，那么存在其他的方法使书写这个程序更加清晰吗？这些规则都具有左右两侧。左侧是我们想要采取的导数的表达式，有右边则是其的替代。用可以匹配的模式，和能够代换的框架，可以得到新的表达式。所以这意味着模式是对源表达式的匹配，并且规则的应用的结果是去产
NoMasp·2015-03-23 20:00

抽象的构件

在我读SICP的过程中，我开始感叹这本书选择Lisp作为表现语言是十
王子亭·2015-03-16 00:00

【SICP归纳】3 层次性数据和符号数据

后来才知道让Lisp输出图形化界面是更高层次的工程，想想还是先把SICP搞定。上一篇博文中我们谈到了复合数据，关于它有两个重点。第一，数据抽象，这也就意味
NoMasp·2015-03-15 15:00
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