This question already has answers here:
Real world use cases of bitwise operators [closed]
(41 answers)
Closed 6 years ago.
In what what real world applications is bit manipulation used?
Any famous algorithm which uses bit manipulation?
One interesting example is the Fast inverse square root.
https://en.wikipedia.org/wiki/Fast_inverse_square_root
Related
This question already has answers here:
C++ cache aware programming
(10 answers)
Closed 7 years ago.
I am profiling my code on various CPUs running Windows7 and my results so far suggest that I need to tune a buffer size proportional to the machine's L2CacheSize or L3CacheSize. Is there a way to obtain these parameters from C++?
You can use the GetLogicalProcessorInformation function to get that. It returns an array of SYSTEM_LOGICAL_PROCESSOR_INFORMATION structures which contain a CACHE_DESCRIPTOR structure, which provides the cache size information.
This question already has answers here:
BigInteger in C?
(4 answers)
Closed 8 years ago.
I'm looking for a way so that I can get big numbers.
I want to calculate 38^n for n>4000
So is there any way to do this?
Kindly help me.
Look for a BigInt library like this one if the unsigned long long (64-bit integer) does not fit your needs.
Since 38^4000 =
13626567354997617056329313518572669871071170880583693359544272980041303981882434734538430960058767177295025923983566648755876881186325460368486197224167007060233768247052629486933889789012295518920202064862370213656621579461608833913900821509100620666110600996588831934295625624174881269739475099253543291971949351958375909705904924125614847402331728307491174234130043557765333856587852136763450074228033057943275251763474040244718003871446278851718437538753553972738188449864081284199350852720967506441771879828977604092893701331872025324453791540567000401652841385183230548306942426747811381344952202704995790135045091236882434632638273097622784399474964071260288840973524580293683712707126132726032058096115050808212994474874887195248086357178602097170972380906461711265125678088349923203375968414475787300592583696065816150079128755226670110739203817178406747936072376786260989121289233458431976862204647875012437031767751018704749869460607366074818959142212892198396374773980500350327658780222474479129859007194457457829138631699788091425513210781560184664312254850195910716334354324281366251167877851974205334475355985568256387781089509361002196647952275789359155111023451749451415734405096655278295174255960345304122475081165484445003142760913586534250626764015379905517010658444442626228678332925600616931303695695506161883152099899363859336729182377570281814058896416875807664402882868124355445335565905063833617714010822965856571393423962785717867701811630985000479945840574458836679738068978432208205049488474929993540051593774645379459275410621407737459680323962561140718740797900009352381301734433124145413190718954715078693891773766465543820020118333909425037946747920952112324716580163881088322718499979305631739834146130913408498900815005646996682256912339033205133816486824614258926495495812784036447453990264570960357479488597566262100857318557132063094971671138328081636423205300001440991841875093227157189180046979201235997836871115178473793331951908545162574227413951298558070125899512700390047047940487152449438682512124512374465180907633872133729735427824770312681013603101057078687642650433926086042263469811785972516780935001257979167301396531650578909144617556401661596286655000890845598227443074432224649650421444669509917690850588828467680365214374983571440413011029311538006314308009334022145676697106884765702897820392205002104976510511690662873648924905859206045090301538364495227369714240000327397892685270724477432224051710235161915341380166322505403047479921207485985826617144630062427543646106264207676267960138097995365712065699367252327692166917027162817512355112577817759333185119496357726652263574955692412766427791636621561003248143162088338810765811925034175243098253477183777981530119336600325069531470597361199726340530012493284901312472359938906404036536403970381273042347532022592036037374925652036435508211829648726060002645001171965651585268749073280713101532058063840348319740158848595441587678957522413199351039043113142029907129705744137232342011968704198807114940460676009450036521225461344010852618106239118154966331660057415602614793721826584529397251289749725656538096388399695143315928518563068548192735206544682378537520506418007926073285706849973274222076317373033059304200101911951067149937028894562722109537797411167898225856420348308410350603384055632474339567057703010340688068370821291318903177717596801407315734010878564418695310254546381520276678538725157608043309023441709322160712160377986536483006949768428055070012131321307517369398293559849470345086292046748890778373027131007888477361435703338650286281943866790521895536089587012314596482938225348353910513764482608946308253045592163757729525262326745493201953185303485264102739959029696399931572287438132772357749175882967079565029225741296582036140259021566923027054743911617278986639492312193679025969190891540930024189366778105054430929215092236023487686440492543667079519662985565417362492072592025055258819162704173072662013949276074302392094104918002731442385963738154377544394436144830710895941012427657480393526992952298836599116927265835864794883149357772532128926114623377650330127681469398680908197842808781573649462943403899309504315010053951097502630531047921616001572581816853481632903644705002543359747980637999901147726746920478281033260422246532219801930828506609799922586505464736354853965408705166237575268884142550705915838361403803760633861291439873689266312094985645627825768264532068068383940009347237832839084518620736293338032805140684318825609037052029320710069076942327055511619384729507413979366221173731875081583527606225142331708054058056316566268463694297799208229967327456031980737573803309723678915050699869715272912792497268191176053411510542893000088350086703903267923064151320399321810627158761446660416500169785103732189707448149719408203646028631800570100383545558186048239744484408082627734589940230907845416949939893008652775458505691974437891034384581573026445318317396853368414228897325531497788743229729964241347151442038312944349207021462075732646443668171786595400861104506016915734670330338318506940647492024589840270503991235013262662584958056139456884168786647861529375426433055592755996647363095606998572938173742273727647855395827384610580791486231441743966364638926656177574517783395990477645234920662029069130520169839954328852889679297698894440289360920229577366598674693945253544348773443008431294122902200275761539883366488016392721682618754525310713687607682663191813572550150753228158785842023491267134367643177590897108661282968536031908401081453990449167116430269199694437799218382709284611544863462398344387527482864615346690281888178491568067973361859477877403761036289855293359103434207477896715048195648273965669239199756276403324120343903889368419203819744433704771664793914154135622085625251617910720554457686952006577578494073537754699513783351789231152535131897837873522492614650699226752457363727673079692328753548477123197857803197559269831202493927130425819248457221653733937060671839872590344351995222910813966529070591698808960588220021008665427193485211880949161819748058663187983592657186472030052147851033490886803897240924656263389646409848702846770248392608384734172415681411506756891468425081693839740848739676180437868697906407065835441491240347225077345140389966302714596712069918261923483301431653997283019346596069376
You definitely need some kind of big int library. You can find one quite easily on Google or even (if you plan only specific operations), write one on your own. For instance, the above result comes from my own calculator, which supports big integer evaluations.
This question already has answers here:
Optimizations for pow() with const non-integer exponent?
(10 answers)
Closed 9 years ago.
I have to raise a number to the power of 1/2.2 which is 0.45454545... many times. Actually I have to do this in a loop. Simple pow/powf is very slow (when I comment out this pow from my loop code it's a loot faster). Is there any way to optimize such operation?
You might give a look at: Optimized Approximative pow() in C / C++
It also includes a benchmark.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
What algorithm gives suggestions in a spell checker?
What algorithm should be used in a C++ program whose aim is to read from a text file and give suggestions for the wrong spelled words ?
Use the Levenshtein distance:
http://thetechnofreak.com/technofreak/levenshtein-distance-implementation-c/
http://murilo.wordpress.com/2011/02/01/fast-and-easy-levenshtein-distance-using-a-trie-in-c/
This question already has answers here:
Bignum libraries for windows?
(4 answers)
Closed 9 years ago.
Is there a library that can be implemented relatively easily in windows?
I made a few functions a while ago which used arrays of numbers to get the desired outcome. I might work at them when I get the time.
But is there any such feature already available that can be implemented into c++ easily?
Apparently people have had luck with using the GNU Multiple Precision Arithmetic Library for Windows.