How can I add very large numbers in C++?

Question

This question is repeated. http://stackoverflow.com/questions/269268/how-to-implement-big-int-in-c — jaircazarin-old-account, Dec 04 '08 at 05:24
Numbers are not necessarily ints so it may not be exactly the same. — tvanfosson, Dec 04 '08 at 05:26
Also Check out here: http://stackoverflow.com/search?q=BigInt+c%2B%2B — Martin York, Dec 04 '08 at 08:28
If you want to perform the multi-precision math yourself, then I suggest you take a look at Donald Knuth's [Art of Computer Programming](https://en.wikipedia.org/wiki/The_Art_of_Computer_Programming). I believe Volume II, Seminumerical Algorithms, Chapter 4, Multiple Precision Arithmetic, is what you are interested in. Also see [How to add 2 arbitrarily sized integers in C++?](https://stackoverflow.com/q/2926219/608639), which provides code for some C++ libraries and OpenSSL. — jww, Aug 29 '17 at 17:52

score 3 · Answer 1 · answered Dec 04 '08 at 05:26

3

answered Dec 04 '08 at 05:26

Ray Tayek

score 1 · Answer 2 · answered Dec 04 '08 at 05:52

1

Do a Google on "Bigint C++" This will provide you with a list of arbitrator precision integer arithmetic libraries.

answered Dec 04 '08 at 05:52

Martin York

score 0 · Answer 3 · answered Dec 04 '08 at 05:24

0

You can find a big decimal implementation at http://speleotrove.com/decimal/

answered Dec 04 '08 at 05:24

tvanfosson

score 0 · Answer 4 · answered Dec 04 '08 at 05:25

0

How big is "very large"? A signed long int can go up to 2,147,483,647 and an unsigned long int can go up to 4,294,967,295.

answered Dec 04 '08 at 05:25

Not accurate sizeof(long) >= sizeof(int). So technically long only has to be as big as int (and on most systems nowadays is just 32). long long (A C extension not yet officially supported by C++) has a minimum of 64 bytes. – Martin York Dec 04 '08 at 05:48
You mean 64 bits, not 64 bytes. – TonJ Dec 04 '08 at 08:24
Accurate. sizeof(long) >= sizeof(int) is not the only requirement; the 32 bits range is another. – MSalters Dec 04 '08 at 09:47

score 0 · Answer 5 · answered Dec 04 '08 at 08:26

0

GMP has a GMPXX C++ wrapper which is kind of nice. GMP supports both integer and floating point numbers, and is LGPL'ed.

I've used it. It's ok, but watch out for creating lots of temporaries. (Potential efficiency hit.)

answered Dec 04 '08 at 08:26

Mr.Ree

score -1 · Answer 6 · answered Dec 04 '08 at 05:22

-1

You could use a library like LiDIA for a 'big integer' class.

answered Dec 04 '08 at 05:22

GEOCHET

6 Answers6