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:

*gmplib.org/manual/index.html

 

[FilledVoid]

This is the right manual:

*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.