收集的一些嵌入式軟件工程師面試題目

1、將一個字符串逆序2、將一個鏈表逆序3、計算一個字節(jié)里(byte)里面有多少bit被置14、搜索給定的字節(jié)(byte)5、在一個字符串中找到可能的最長的子字符串6、字符串轉(zhuǎn)換為整數(shù)7、整數(shù)轉(zhuǎn)換為字符串威盛什么是平衡二叉樹？編寫一個刪除平衡二叉樹的程序？寫一個程序，求有向有權(quán)圖兩點之間的最小權(quán)？3?根據(jù)你的理解，寫出Cstring類的構(gòu)造函數(shù)和析構(gòu)函數(shù)？4?使用C語言實現(xiàn)對ini文件的訪問，使程序可以對int，double，字符串類進行讀寫。5.nXn個方格(n為任意整數(shù))，定義若兩個格有公共邊則稱兩個格相鄰。現(xiàn)將個格中的N個格子圖黑，使每個格子都與黑格子相鄰。試編程，使N最小。l.static變量和static函數(shù)各有什么特點？3?描述一下嵌入式基于ROM的運行方式基于ram的運行方式有什么區(qū)別。task有幾種狀態(tài)？task有幾種通訊方式？C函數(shù)允許重入嗎？嵌入式操作系統(tǒng)和通用操作系統(tǒng)有什么差別？一面，技術(shù)面VxWorks、uc/OS、Palm嵌入式系統(tǒng)操作系統(tǒng)的區(qū)別？做嵌入式軟件開發(fā)和普通桌面軟件開發(fā)有什么區(qū)別？c語言問題，union和struct的區(qū)別？sizeof(—大堆變量)，如果用這個函數(shù)分配內(nèi)存的大小一定與定義相同嗎？解釋什么是優(yōu)先級反轉(zhuǎn)。Canstructuresbepassedtothefunctionsbyvalue?Whycannotarraysbepassedbyvaluestofunctions?Advantagesanddisadvantagesofusingmacroandinlinefunctions?Whathappenswhenrecursionfunctionsaredeclaredinline?Scopeofstaticvariables?Differencebetweenobjectorientedandobjectbasedlanguages?Multipleinheritance-objectscontainhowmanymultiplyinheritedancestor?Whatarethe4differenttypesofinheritancerelationship?Howwouldyoufindoutthenoofinstanceofaclass?Isjavaapureobjectorientedlanguage?Why?Orderofconstructoranddestructorcallincaseofmultipleinheritance?Canuhaveinlinevirtualfunctionsinaclass?Whenyouinheritaclassusingprivatekeywordwhichmembersofbaseclassarevisibletothederivedclass?Whatistheoutputofprintf("\nab\bcd\ref");->ef#definecat(x,y)x##yconcatenatesxtoy.Butcat(cat(1,2),3)doesnotexpandbutgivespreprocessorwarning.Why?Canyouhaveconstantvolatilevariable?Yes,youcanhaveavolatilepointer?++*ipincrementswhat?itincrementswhatippointstoOperationsinvolvingunsignedandsigned一unsignedwillbeconvertedtosigneda+++b->(a++)+bmalloc(sizeof(O))willreturn一validpointermain(){fork();fork();fork();printf("helloworld");}一willprint8times.Arrayofptstofunctions一void(*fptr[10])()Whichwayofwritinginfiniteloopsismoreefficientthanothers?thereare3ways.#error一whatitdoes?Howisfunctionitoa()written?Whotoknowwethersystemusesbigendianorlittleendianformatandhowtoconvertamongthem?Whatisinterruptlatency?Whatisforwardreferencew.r.t.pointersinc?Howisgenericlistmanipulationfunctionwrittenwhichacceptselementsofanykind?Whatisthedifferencebetweenhardreal-timeandsoftreal-timeOS?Whatisinterruptlatency?Howcanyourecuceit?Whatisthedifferncebetweenembeddedsystemsandthesysteminwhichrtosisrunning?Howcanyoudefineastructurewithbitfieldmembers?WhatarethefeaturesdifferentinpSOSandvxWorks?Howdoyouwriteafunctionwhichtakes2arguments-abyteandafieldinthebyteandreturnsthevalueofthefieldinthatbyte?WhatarethedifferentstorageclassesinC?WhatarethedifferentqualifiersinC?WhatarethedifferentBSDandSVR4communicationmechanisms一位資深的嵌入式項目經(jīng)理曾這樣對我說:搞嵌入式要往下走，要搞底層要搞算法，因為它們比較有前途。EmbeddedfirmwareinterviewquestionsWritefunctioninCthatgetsarrayofchars,andsearchforthelongestsequenceofrepeatedly1bits.Itreturnsthethefirstbitplaceinthesequenceandthenumberof1bitsinthesequence.-(a)loopof2A0,2A1,?…,2A7isdonewith1vvjwhen0<=j<=7.(b)Takecareofrememberingthefirstplaceofthebitsequenceyouarecounting.Youhave16bitregisterthatincrementitselfandloopsabouteverysecond.Whentheregisterreach0xffffitwillissueaninteruptandwillrunthefunctionupdate_time().Thereisafunctionunsignedlongget_time()thatreturnsthetime.Youneedtoimplementthetwofunctions.-(a)Youneedtocounteveryinterruptinordertosavethenumberofseconds.(b)Thecounterwillbethe16bitMSB,andtheactualregisterwillbe16bitLSB.(c)Iftheregisterwillbeat~0xfff0,youwillreturnMSBthatisnotcorrect,becauseyouwillreadthecounter,theninterruptwillaccureandincrementbyone.Nowyouhavecounterthatisnotcorrect.(d)Youneedtocheckforthe(c)problem,andifyoucatchtheproblem,youneedtoreadonceagaintheregisterandthecounterbeforeyoureturnthem.Youdependonthefacttheyouhaveaboutanotherseconduntiltheregisterwillloop.對嵌入式初學者有必要解釋一下什么是firmware，中文為固件，一般跑在DSP上，是比較底層的東西，也是目前比較熱門和有挑戰(zhàn)性的嵌入式工種。從下面的一則招聘信息中我們也可以知道Firmware大概干些什么。招聘職位：Firmwareengineer/SeniorFirmwareengineer職位描述：FirmwareEngineerResponsibility:DevelopingoradaptinghardwaredevicedriverDevelopingoradaptingembeddedapplicationsoftwareforVideoCodecImplementingsoftwareonsystem-on-chipsolutionusingacombinationofCandassemblyprogramminglanguages.TuningsoftwareforperformanceRequirements:.SolidskillsdevelopinginCandassemblylanguages,Experiencedevelopinganddebuggingembeddedsystems(ARC,ARM,MIPS,SPARC,...).familiarwithperipheralsandprotocols,suchasI2C,UART,USB,LCD,Ethernet,IDE,SD,TCP/IP,RTP...,KnowledgeofVideoCODECstandardandprinciple,eg:MPEG-1/2/4,H.264ispreferred.goodatEnglish,teamplayer,positivepersonality,andabletoworkunderpressuretomeetdeadlines.BSinElectricalEngineering,ComputerScience,Abilitytolearnandapplynewknowledgequickly職位要求：SeniorFirmwareEngineerResponsibility:Developmentofembeddedsoftwaresystemsforvideoprocessing,involveinallphasesoftheembeddedsoftwaredevelopmentcycleincludingresearch,design,implementation,systemdebug,anddocumentation.Top-levelsystemfirmwareintegration;Systemperformancetrimmingandimprovement;Requirements:Experiencedevelopinganddebuggingembeddedsystems(ARC,ARM,MIPS,SPARC,...),especiallyinaRTOSenvironment(ThreadX,uclinux,MQX).familiarwithperipheralsandprotocols,suchasI2C,UART,USB,LCD,Ethernet,IDE,SD,TCP/IP,RTP..GoodknowledgeofVideoCODECstandardandprinciple,(eg:MPEG-1/2/4,H.264),hands-on.experi