Need help with using GMP BigNum Library

[FilledVoid]

Hi all,
I have been working on Project Euler questions and I'm trying to understand how to use this GMP Bignum library and I've read through a bit of the documentation but this is way way more complex than what I expected lol. I'd appreciate if soeone could either post a few SIMPLE examples using it. If you could attach the code, that woulds be great. Please dont post the ones in the demo folder of the gmp library cause I can barely understand them at all lol.
Thanks

[QwertyManiac]

Here's a simple code which adds and subtracts 2 integers among 3:

#include <gmp.h>

int main(void)
{
// We declare a few BigNum Integer
mpz_t I, K, M;

// Some BigNum Floats (Not gonna use them)
// Just demo
mpf_t U,J,N;

int n;

// Initialize the Integer I as 0
// set a value for the rest two (K and M)

// We need to initialize ANY BigNum value
// Its a must

mpz_init(I); // Initialized with 0

mpz_init(K);

mpz_set_si(K, -3000000);
// si means Signed Integer
// set_* is used to set values

mpz_init_set_ui(M, 999999999);
// Initialized and set via Unsigned at a time

// Similarly one can convert via Double, Strings, etc
// and even set via other mpz_t values
// Also use xxx_clear() to clear

// Add M, K and store in I
mpz_add(I,M,K);

// Subtraction, another example
mpz_sub(M,K,I);

gmp_printf("I = %Zd, K = %Zd, M = %Zd \n", I, K, M);

// Refer the manual for other _functions_ relating to integers

return 0;
}

/*

Note on GMP in general

There are 3 basic types of Numbers in GMP
Integer - Represented as "Z"
Float - Represented as "F"
Rational - Represented as "Q"

There are some more types, such as Limbs and so,
but I don't know much about them.

So in gmp_printf(), the strings obviously are:
%Z<format> for Integer
%F<format> for Float
%Q<format> for Rational

Where <format> can be any C-allowed printf() type such as:
d - Integer
f - Float
x - Hex

gmp_scanf()'s the same

P.s. Heard that stuff for O/P and I/P are easier in C++ but,
I prefer C
*/

See it in some editor which highlights comments out at least.

[Sykora]

Are you sure you checked the manual? It seemed pretty simple to me. Just read the part on initialization, then all the arithmetic functions, then the I/O. That should be all you need.

[ChaiTan3]

Even I had decided to use BigNum library for some of ProjectEuler's problems. But due to its complexity, learning python turned out to be a simpler option(learning loops and functions hardly takes 10 min)

[FilledVoid]

QwertM : Thank you for the guidance :) That explains alot.


Are you sure you checked the manual? It seemed pretty simple to me. Just read the part on initialization, then all the arithmetic functions, then the I/O. That should be all you need.

Hmm Maybe Im looking at the wrng manual then. But I felt that it was way too complex :| .

Even I had decided to use BigNum library for some of ProjectEuler's problems. But due to its complexity, learning python turned out to be a simpler option(learning loops and functions hardly takes 10 min)

yeah I've beent empted to change to Python but I'd like to make sure I atleast try in C befoer I give up.

[QwertyManiac]

This is the right manual:

http://gmplib.org/manual/index.html

[FilledVoid]

This is the right manual:

http://gmplib.org/manual/index.html
Thank you

[Sykora]

The entire python standard library _is_ written in C. So if you maximize your usage of builtins, you'll be able to get C's speed, and write in python, which is heavenly.