Hi David, On Wed, Jan 11, 2012 at 8:30 PM, Kronheim, David (Contr) < david.kronh...@ftr.com> wrote:
> Hi Tim: > > I don't trust picking off the first or last 10 digits, without using > BigInt. Without BigInt, Perl will give a sum with your code but, the digits > in the answer will be > different. Frequently I find using examples based on texts easier than > CPAN documentation. The subroutine I got from Learning Perl, it separates > every 3digits with commas. I apologize for the late reply, my email was > unavailable to me. Based on Programming Perl, BigInt expects strings (like > with new) for input. Once a BigInt object is created, operations like + > should be overloaded for that BigInt object. > > #!/usr/bin/perl > use warnings; > use strict; > use 5.012; # this script requires Perl 5.12 or greater > use Math::BigInt; > # euler_13.pl > =begin comment > http://projecteuler.net/problem=13 > Work out the first ten digits of the sum of the following one-hundred > 50-digit numbers. > =end comment > =cut > open (my $fh, '<', "Fifty_hundred.txt") or die "Could not open > Fifty_hundred.txt: $!" ; > #my $sum = Math::BigInt->new('+0'); > my $sum; > while (<$fh>) { > chomp; > $sum += $_; > } > close $fh; > say big_int($sum) ; for me there is no need writing a new subroutine when sprintf can express your answer $sum, in a floating-point numbers though string, then pick out the first 10 digits using unpack e.g: print unpack "a10",sprintf "%f",$sum; #5537376230 which of course is the right answer! > > sub big_int { > my $number = shift @_; > # Add one comma each time through the do-nothing loop > 1 while $number =~ s/^(\d+)(\d\d\d)/$1,$2/; > $number; > } > > > Sincerely, > David Kronheim > Production Support Tier II > Gateway Error Correction, VZ450 EDI, EDI Billing, & Metakey/LIA > 484-213-1315 > _________________________________ > From: timothy adigun [2teezp...@gmail.com] > Sent: Saturday, December 31, 2011 4:11 AM > To: Jeswin > Cc: beginners > Subject: Re: working with large integers > > Hi Jeswin, > >>>>> "Shlomi" == Shlomi Fish <shlo...@shlomifish.org> writes: > Shlomi> Hi Jeswin, > Shlomi> On Thu, 29 Dec 2011 11:40:09 -0500 > Shlomi> Jeswin <phillyj...@gmail.com> wrote: > Shlomi> > Hi, > Shlomi> > I'm doing one of the Project Euler exercises which asks > the sum of 100 > Shlomi> > fifty-digit numbers[1]. My code is 2 parts: > Solved this same problem using perl. Please check below: > Shlomi> > > Shlomi> > I open the text file containing the digits and put into an > array: > Shlomi> > ========================BEGIN_CODE========================= > Shlomi> > open (F, "Fifty_hundred.txt") || die "Could not open > Fifty_hundred.txt: $!\n"; > Shlomi> > > Shlomi> 1. You should use lexical file handles. > Shlomi> 2. You should use three arguments open. > Shlomi> open (my $fh, '<', "Fifty_hundred.txt") or die "Could not > open > Shlomi> Fifty_hundred.txt: $!". > Shlomi> > @numbers = <F>; > Shlomi> It would be a better idea to read it line by line, using > while. > Shlomi> > close F; > Shlomi> > ========================END_CODE=========================== > Shlomi> > > Shlomi> > Next I sum the values in the array: > Shlomi> > ========================BEGIN_CODE========================= > Shlomi> > $sum = 0; > Shlomi> > for (@numbers) { > Shlomi> > $sum += $_; > Shlomi> > } > Shlomi> > ========================END_CODE=========================== > Shlomi> > > Shlomi> > I get an answer but its wrong (according to Project > Euler). Now I am > Shlomi> > looking into the BigNum functions but I am not sure how > they work and > Shlomi> > don't really know how to use it. > To solve this problem, you don't really need the module > Math::BigInt. perl will handle this nicely! However, if you still want to > check out the module, why not? > Shlomi> See: https://metacpan.org/module/Math::BigInt - you might > need some > Shlomi> introduction to object-oriented Perl. You can find it in the > book "Modern Perl" > Shlomi> and in other resources - > http://perl-begin.org/topics/object-oriented/ . > > [Code] > > #!/usr/bin/perl > use warnings; > use strict; > > my $sum; > while(<DATA>){ > $sum+=$_; > } > > print $sum; # Please figure out how to *pick* out the first 10 digits > # I used sprinf and unpack. > > __DATA__ > 37107287533902102798797998220837590246510135740250 > 46376937677490009712648124896970078050417018260538 > 74324986199524741059474233309513058123726617309629 > 91942213363574161572522430563301811072406154908250 > 23067588207539346171171980310421047513778063246676 > 89261670696623633820136378418383684178734361726757 > 28112879812849979408065481931592621691275889832738 > 44274228917432520321923589422876796487670272189318 > 47451445736001306439091167216856844588711603153276 > 70386486105843025439939619828917593665686757934951 > 62176457141856560629502157223196586755079324193331 > 64906352462741904929101432445813822663347944758178 > 92575867718337217661963751590579239728245598838407 > 58203565325359399008402633568948830189458628227828 > 80181199384826282014278194139940567587151170094390 > 35398664372827112653829987240784473053190104293586 > 86515506006295864861532075273371959191420517255829 > 71693888707715466499115593487603532921714970056938 > 54370070576826684624621495650076471787294438377604 > 53282654108756828443191190634694037855217779295145 > 36123272525000296071075082563815656710885258350721 > 45876576172410976447339110607218265236877223636045 > 17423706905851860660448207621209813287860733969412 > 81142660418086830619328460811191061556940512689692 > 51934325451728388641918047049293215058642563049483 > 62467221648435076201727918039944693004732956340691 > 15732444386908125794514089057706229429197107928209 > 55037687525678773091862540744969844508330393682126 > 18336384825330154686196124348767681297534375946515 > 80386287592878490201521685554828717201219257766954 > 78182833757993103614740356856449095527097864797581 > 16726320100436897842553539920931837441497806860984 > 48403098129077791799088218795327364475675590848030 > 87086987551392711854517078544161852424320693150332 > 59959406895756536782107074926966537676326235447210 > 69793950679652694742597709739166693763042633987085 > 41052684708299085211399427365734116182760315001271 > 65378607361501080857009149939512557028198746004375 > 35829035317434717326932123578154982629742552737307 > 94953759765105305946966067683156574377167401875275 > 88902802571733229619176668713819931811048770190271 > 25267680276078003013678680992525463401061632866526 > 36270218540497705585629946580636237993140746255962 > 24074486908231174977792365466257246923322810917141 > 91430288197103288597806669760892938638285025333403 > 34413065578016127815921815005561868836468420090470 > 23053081172816430487623791969842487255036638784583 > 11487696932154902810424020138335124462181441773470 > 63783299490636259666498587618221225225512486764533 > 67720186971698544312419572409913959008952310058822 > 95548255300263520781532296796249481641953868218774 > 76085327132285723110424803456124867697064507995236 > 37774242535411291684276865538926205024910326572967 > 23701913275725675285653248258265463092207058596522 > 29798860272258331913126375147341994889534765745501 > 18495701454879288984856827726077713721403798879715 > 38298203783031473527721580348144513491373226651381 > 34829543829199918180278916522431027392251122869539 > 40957953066405232632538044100059654939159879593635 > 29746152185502371307642255121183693803580388584903 > 41698116222072977186158236678424689157993532961922 > 62467957194401269043877107275048102390895523597457 > 23189706772547915061505504953922979530901129967519 > 86188088225875314529584099251203829009407770775672 > 11306739708304724483816533873502340845647058077308 > 82959174767140363198008187129011875491310547126581 > 97623331044818386269515456334926366572897563400500 > 42846280183517070527831839425882145521227251250327 > 55121603546981200581762165212827652751691296897789 > 32238195734329339946437501907836945765883352399886 > 75506164965184775180738168837861091527357929701337 > 62177842752192623401942399639168044983993173312731 > 32924185707147349566916674687634660915035914677504 > 99518671430235219628894890102423325116913619626622 > 73267460800591547471830798392868535206946944540724 > 76841822524674417161514036427982273348055556214818 > 97142617910342598647204516893989422179826088076852 > 87783646182799346313767754307809363333018982642090 > 10848802521674670883215120185883543223812876952786 > 71329612474782464538636993009049310363619763878039 > 62184073572399794223406235393808339651327408011116 > 66627891981488087797941876876144230030984490851411 > 60661826293682836764744779239180335110989069790714 > 85786944089552990653640447425576083659976645795096 > 66024396409905389607120198219976047599490197230297 > 64913982680032973156037120041377903785566085089252 > 16730939319872750275468906903707539413042652315011 > 94809377245048795150954100921645863754710598436791 > 78639167021187492431995700641917969777599028300699 > 15368713711936614952811305876380278410754449733078 > 40789923115535562561142322423255033685442488917353 > 44889911501440648020369068063960672322193204149535 > 41503128880339536053299340368006977710650566631954 > 81234880673210146739058568557934581403627822703280 > 82616570773948327592232845941706525094512325230608 > 22918802058777319719839450180888072429661980811197 > 77158542502016545090413245809786882778948721859617 > 72107838435069186155435662884062257473692284509516 > 20849603980134001723930671666823555245252804609722 > 53503534226472524250874054075591789781264330331690 > > [/Code] > Regards. > Tim > > This communication is confidential. Frontier only sends and receives > email on the basis of the terms set out at > http://www.frontier.com/email_disclaimer. > -- Tim
