how do we print a number that's greater than 2^32-1 with int and float? (is it even possible?)

Question

how do we print a number that's greater than 2^32-1 with int and float? (is it even possible?)

Answer 1

How does your variable contain a number that is greater than 2^32 - 1? Short answer: It'll probably be a specific data-structure and assorted functions (oh, a class?) that deal with this.

Given this data structure, how do we print it? With BigInteger_Print(BigInteger*) of course :)

Really though, there is no correct answer to this, as printing a number larger than 2^32-1 depends entirely upon how you're storing that number.

Answer 2

If you are talking about int64 types, you can try %I64u, %I64d, %I64x, %llu, %lld

Answer 3

On common hardware, the largest float is (2^128 - 2^104), so if it's smaller than that, you just use %f (or %g or %a) with printf( ).

For int64 types, JustJeff's answer is spot on.

The range of double (%f) extends to nearly 2^1024, which is really quite huge; on Intel hardware, when the long double (%Lf) type corresponds to 80-bit float, the range of that type goes up to 2^16384.

If you need larger numbers than that, you need to use a library (which will likely have its own print routines) or roll your own representation and provide your own printing support.

Answer 4

More theoretically: suppose you have a very very very large number stored somewhere somehow; if so, I suppose that you are somehow able to do math on that number, otherwise it would be quite pointless storing it.

If you can do math on it, just divide the bignumber by ten (10); store the remainder somewhere. Repeat until the result is smaller than 10. When it's smaller than ten, print it, then print the remainders, from the last to the first. Finish.

You can speed up things by dividing for the largest power of 10 that you are able to print without effort (on 32 bit, 1'000'000'000).

Edit: pseudo code:

#include <stdio.h>
#include <math.h>
#include <math_with_very_very_big_num.h>

int main(int argc, char **argv) {
  very_very_big_num bignum = someveryverybignum;
  very_very_big_num quot;
  int size = (int) floor(vvbn_log10(bignum)) + 1;
  char *result = calloc(size, sizeof(char));

  int i = 0;
  do {
    quot = vvbn_divide(bignum, 10);
    result[i++] = (char) vvbn_remainder(bignum, 10) + '0';
    bignum = quot;
  } while (vvbn_greater(bignum,  9));
  result[i] = (char) vvbn_to_i(bignum) + '0';
  while(i >= 0)
    printf("%c", result[i--]);
  printf("\n");
}

(I wrote this using long, than translating it with veryverybignum stuff; it worked with long, unluckily I cannot try this version, so please forgive me if I made transation errors...)