algorithm to figure out how many bytes are required to hold an int

Question

sorry for the stupid question, but how would I go about figuring out, mathematically or using c++, how many bytes it would take to store an integer.

Answer 1

If you mean from an information theory point of view, then the easy answer is:

log(number) / log(2)

(It doesn't matter if those are natural, binary, or common logarithms, because of the division by log(2), which calculates the logarithm with base 2.)

This reports the number of bits necessary to store your number.

If you're interested in how much memory is required for the efficient or usual encoding of your number in a specific language or environment, you'll need to do some research. :)

The typical C and C++ ranges for integers are:

 char    1 byte
 short   2 bytes
 int     4 bytes
 long    8 bytes

If you're interested in arbitrary-sized integers, special libraries are available, and every library will have its own internal storage mechanism, but they'll typically store numbers via 4- or 8- byte chunks up to the size of the number.