I am generally trying to convert the results from an I2C chip into the correct output. To do this I need to compute some fairly large numbers.

My starting point for now is 1072953^2, I found the library Bignumber.h, and while it seems great at calculating large numbers it seems I can only feed ints into the library.

BigNumber a = 1072953; returns 24377. I dug though the .h files for the library and it seems that I can only give the function ints;

// constructors
BigNumber (); // default constructor
BigNumber (const char * s); // constructor from string
BigNumber (const int n); // constructor from int
// copy constructor
BigNumber (const BigNumber & rhs);

I tried a couple way, both by and and in MatLAB to simplify the equations to make this possible. This is how I got to the x^2 value. This seems to be as far as I can get with out the use of some large number code.

I tried a couple way, both by and and in MatLAB to simplify the equations to make this possible. This is how I got to the x^2 value. This seems to be as far as I can get with out the use of some large number code.

Well, I don't doubt that you need to square it. But do you really need the precision of the diameter of a pin vs. the distance between Jupiter and the Sun as a result?

My starting point for now is 1072953^2, I found the library Bignumber.h, and while it seems great at calculating large numbers it seems I can only feed ints into the library.

BigNumber a = 1072953;

returns 24377.

Weird that there isn't a constructor for long arguments. How about:

BigNumber a = 811;
a = a * 1323; /* 1072953 */
a = a * a; /* squared */

(only works in a code path, not as an initializer.) (I hope 1072953 wasn't supposed to be prime...)
You could use int64_t for this, but the last I heard, int64 support wasn't very good, so bignumber might even be better.

(did you know that older floating point formats had a magnitude limit of about 10^38, and you couldn't easily use those computers for physics homework involving "hBar squared"? I don't remember what the point of the physics was, but that HW was a real education in the limits of computers!)