View Full Version : Gmp

October 24th, 2011, 11:40 PM
I am wondering how to add a couple dozen 50 digit integers in GMP. I know how to use C++ just not gmp. When I try to use any calculator etc etc. It just gives me a non-precise number.

October 25th, 2011, 12:36 AM
This is covered in chapter 12 of gmp-doc, you know. It doesn't look all that tough.

October 25th, 2011, 01:06 AM
Yeah but I am a n00b and need extra help. So far I have this

#include <iostream>
#include <gmp.h>
using namespace std;

int main()
mpz_t num;

How to do I add an integer to that num. I don't understand the documentation.

October 25th, 2011, 02:30 AM
Oh common just provide me with an example of creating a GMP int and adding a number to it. PWEESE?

October 25th, 2011, 02:32 AM
Well for c++, you don't use gmp.h. It should be something more like:

#include <gmpxx.h>
#include <iostream>
using namespace std;

int main (void)
mpz_class a, b, c;
a = 1234;
b = "-5678";
c = a+b;
cout << "sum is " << c << "\n";
cout << "absolute value is " << abs(c) << "\n";
return 0;

(The above is straight out of the chapter I mentioned.)

EDIT: Here's a compile line:

g++ -o sum sum.cc -lgmpxx -lgmp

Then, when you run it:

$ ./sum
sum is -4444
absolute value is 4444

Pretty easy, I'd say (if you opened the doc, that is).