Question

I understand that the standard says that the size of a long integer is implementation dependant, but I am not sure why.

All it needs to do is to be able to store -2147483647 to 2147483647 or 0 to 4294967295.

Assuming that 1 byte is 8 bits, this should never need more than 4 bytes. Is it safe to say, then, that a long integer will take more than 4 bytes only if a byte has less than 8 bits? Or could there be other possibilities as well? Like maybe inefficient implementations wasting space?

Answer 1

The extra bytes aren’t a waste of space. A larger range is quite useful. The standard specifies minimum ranges, not the precise range itself; there’s nothing wrong with having wider types.

When the standard originally specified an int should be at least 16 bits, common processors had registers no larger than that. Representing a long took two registers and special operations!

But then 32 bits became the norm, and now ints are 32 bits everywhere and longs are 64. Nowadays most processors have 64-bit instructions, and a long can often be stored in a single register.