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#2
zklhp2014-04-03 08:22
浮点数因为有精度问题 不能直接比较 可以用这种方法 设定一个精度
 程序代码：const double MIN = 1E-5; for (i = 0; i - 10.0 < MIN; i += 0.1) { cout << i << endl; } |
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#3
rjsp2014-04-03 09:30
知不知浮点数的“浮点”是什么意思？
知不知“十进制的有限不循环小数”用二进制表示可能是“循环小数”？ 0.0 + 0.1 + 0.1 + …… 一种可能是： 程序代码：0.0 0.1000000000000000055511151231257827021181583404541015625 0.200000000000000011102230246251565404236316680908203125 0.3000000000000000444089209850062616169452667236328125 0.40000000000000002220446049250313080847263336181640625 0.5 0.59999999999999997779553950749686919152736663818359375 0.6999999999999999555910790149937383830547332763671875 0.79999999999999993338661852249060757458209991455078125 0.899999999999999911182158029987476766109466552734375 0.99999999999999988897769753748434595763683319091796875 1.0999999999999998667732370449812151491641998291015625 1.1999999999999999555910790149937383830547332763671875 1.3000000000000000444089209850062616169452667236328125 1.4000000000000001332267629550187848508358001708984375 1.5000000000000002220446049250313080847263336181640625 1.6000000000000003108624468950438313186168670654296875 1.7000000000000003996802888650563545525074005126953125 1.8000000000000004884981308350688777863979339599609375 1.9000000000000005773159728050814010202884674072265625 2.000000000000000444089209850062616169452667236328125 2.10000000000000053290705182007513940334320068359375 2.200000000000000621724893790087662637233734130859375 2.300000000000000710542735760100185871124267578125 2.400000000000000799360577730112709105014801025390625 2.50000000000000088817841970012523233890533447265625 2.600000000000000976996261670137755572795867919921875 2.7000000000000010658141036401502788066864013671875 2.800000000000001154631945610162802040576934814453125 2.90000000000000124344978758017532527446746826171875 3.000000000000001332267629550187848508358001708984375 3.10000000000000142108547152020037174224853515625 3.200000000000001509903313490212894976139068603515625 3.30000000000000159872115546022541821002960205078125 3.400000000000001687538997430237941443920135498046875 3.5000000000000017763568394002504646778106689453125 3.600000000000001865174681370262987911701202392578125 3.70000000000000195399252334027551114559173583984375 3.800000000000002042810365310288034379482269287109375 3.900000000000002131628207280300557613372802734375 4.0000000000000017763568394002504646778106689453125 4.10000000000000142108547152020037174224853515625 4.2000000000000010658141036401502788066864013671875 4.300000000000000710542735760100185871124267578125 4.4000000000000003552713678800500929355621337890625 4.5 4.5999999999999996447286321199499070644378662109375 4.699999999999999289457264239899814128875732421875 4.7999999999999989341858963598497211933135986328125 4.89999999999999857891452847979962825775146484375 4.9999999999999982236431605997495353221893310546875 5.099999999999997868371792719699442386627197265625 5.1999999999999975131004248396493494510650634765625 5.2999999999999971578290569595992565155029296875 5.3999999999999968025576890795491635799407958984375 5.499999999999996447286321199499070644378662109375 5.5999999999999960920149533194489777088165283203125 5.69999999999999573674358543939888477325439453125 5.7999999999999953814722175593487918376922607421875 5.899999999999995026200849679298698902130126953125 5.9999999999999946709294817992486059665679931640625 6.099999999999994315658113919198513031005859375 6.1999999999999939603867460391484200954437255859375 6.299999999999993605115378159098327159881591796875 6.3999999999999932498440102790482342243194580078125 6.49999999999999289457264239899814128875732421875 6.5999999999999925393012745189480483531951904296875 6.699999999999992184029906638897955417633056640625 6.7999999999999918287585387588478624820709228515625 6.8999999999999914734871708787977695465087890625 6.9999999999999911182158029987476766109466552734375 7.099999999999990762944435118697583675384521484375 7.1999999999999904076730672386474907398223876953125 7.29999999999999005240169935859739780426025390625 7.3999999999999896971303314785473048686981201171875 7.499999999999989341858963598497211933135986328125 7.5999999999999889865875957184471189975738525390625 7.69999999999998863131622783839702606201171875 7.7999999999999882760448599583469331264495849609375 7.899999999999987920773492078296840190887451171875 7.9999999999999875655021241982467472553253173828125 8.09999999999998721023075631819665431976318359375 8.1999999999999868549593884381465613842010498046875 8.299999999999986499688020558096468448638916015625 8.3999999999999861444166526780463755130767822265625 8.4999999999999857891452847979962825775146484375 8.5999999999999854338739169179461896419525146484375 8.699999999999985078602549037896096706390380859375 8.7999999999999847233311811578460037708282470703125 8.89999999999998436805981327779591083526611328125 8.9999999999999840127884453977458178997039794921875 9.099999999999983657517077517695724964141845703125 9.1999999999999833022457096376456320285797119140625 9.299999999999982946974341757595539093017578125 9.3999999999999825917029738775454461574554443359375 9.499999999999982236431605997495353221893310546875 9.5999999999999818811602381174452602863311767578125 9.69999999999998152588887023739516735076904296875 9.7999999999999811706175023573450744152069091796875 9.899999999999980815346134477294981479644775390625 9.9999999999999804600747665972448885440826416015625 10.0999999999999801048033987171947956085205078125 10.1999999999999797495320308371447026729583740234375 |
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#4
hubinyes2014-04-03 11:31
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