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+---- Thread: [C] C++ Data type bigger than long long?! (/showthread.php?tid=4398551)
C++ Data type bigger than long long?! - Srgjan-LDTeam - Aug 16, 2014
So im trying to solve a little problem, it looks like this:
Code
"n! means n × (n − 1) × ... × 3 × 2 × 1
For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800,
and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.
Find the sum of the digits in the number 100!"so when i call my function with parameter as value 10, my program returns 3628800,
so my code is right but there is another problem, when i call my function with parameter as value 100 which in this case (100 is needed), long long data type wont capture whole number in it, since the return-number is too big for long long,
What can i use to solve this problem? is there anything bigger than long long?
i already tried
Code
unsigned __int64 && unsigned long longSorry if its messed up a little :) and tnx in advance...
* - Mr. Dr. Prof. Patrick - Aug 16, 2014
i do not think there is, the maximum an unsigned int in C/C++ is said to be able to hold is 4,294,967,295 or 0xffffff and im sure the factorial of 100 is much bigger than that
but a part of being a programmer is solving your problems with what you have.. so i bet you can find a work around somehow.. so enjoy!
* - Masm4ever - Aug 16, 2014
(Aug 16, 2014 07:28 AM)adv3nt Wrote: i do not think there is, the maximum an unsigned int in C/C++ is said to be able to hold is 4,294,967,295 or 0xffffff
While that is correct, it is irrelevant. A long long uses 64 bits, an unsigned int only 32.
* - dberube - Aug 16, 2014
The only solution I see is using big integers. Their only limit in size is how much RAM you have.
A quick google search returned this: https://mattmccutchen.net/bigint/
* - Mr. Dr. Prof. Patrick - Aug 16, 2014
(Aug 16, 2014 07:53 AM)Masm4ever Wrote: While that is correct, it is irrelevant. A long long uses 64 bits, an unsigned int only 32.
yea i was making that comment with basic knowledge ive gotten poking around
* - Crypt0leucus - Aug 16, 2014
(Aug 16, 2014 07:11 AM)Srgjan-LDTeam Wrote: So im trying to solve a little problem, it looks like this:
Code"n! means n × (n − 1) × ... × 3 × 2 × 1
For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800,
and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.
Find the sum of the digits in the number 100!"
so when i call my function with parameter as value 10, my program returns 3628800,
so my code is right but there is another problem, when i call my function with parameter as value 100 which in this case (100 is needed), long long data type wont capture whole number in it, since the return-number is too big for long long,
What can i use to solve this problem? is there anything bigger than long long?
i already triedCodeunsigned __int64 && unsigned long long
Sorry if its messed up a little :) and tnx in advance...
I have made an example for you using classes and a linked list representation of the big int. Maybe this will help you figure something out.
Download here: https://www.dropbox.com/sh/a611q85kloblwvj/AAD4TWJNobnDaSjXXjzex8jDa
* - 6577657534735 - Aug 16, 2014
Look up arbitrary precision arithmetic libraries
https://gmplib.org/
* - anikain - Aug 16, 2014
cough Float cough cough malloc cough
* - Сlassy - Aug 17, 2014
Last time I saw a guy solve this with C++ was with patterns.
What I mean by that is study the pattern of sums and the digits of the factorials from ex. 1 to 20.
Bruteforcing is not always the best way to go. I cannot say if that applies here or not, but keep it in mind when doing projecteuler.
* - 0xDEAD10CC - Aug 17, 2014
The other hack would be to store the known result in a string and add the numeric digits from characters extracted from the string, but technically this would still be cheating since your program didn't calculate the result of that factorial. :)