Should I use 'long' instead of 'int' on 64-bits in langs with fixed type size (like Java, C#)

Question

In 10, or even 5 years there will be no [Edit2: server or desktop] 32-bit CPUs.

So, are there any advantages in using int (32bit) over long (64bit) ?
And are there any disadvantages in using int ?

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Edit:

1. By 10 or 5 years I meant on vast majority of places where those langs are used

2. I meant which type to use by default. This days I won't even bother to think if I should use short as cycle counter, just for(int i.... The same way long counters already win

3. registers are already 64-bit, there is already no gain in 32 bit types. And I think some loss in 8 bit types (you have to operate on more bits then you're using)

Answer 1

32-bit is still a completely valid data type; just like we have 16-bit and bytes still around. We didn't throw out 16-bit or 8-bit numbers when we moved to 32-bit processors. A 32-bit number is half the size of a 64-bit integer in terms of storage. If I were modeling a database, and I knew the value couldn't go higher than what a 32-bit integer could store; I would use a 32-bit integer for storage purposes. I'd do the same thing with a 16-bit number as well. A 64-bit number takes more space in memory as well; albeit not anything significant given today's personal laptops can ship with 8 GB of memory.

There is no disadvantage of int other than it's a smaller data type. It's like asking, "Where should I store my sugar? In a sugar bowl, or a silo?" Well, that depends on entirely how much sugar you have.

Processor architecture shouldn't have much to do with what size data type you use. Use what fits. When we have 512-bit processors, we'll still have bytes.

EDIT:

To address some comments / edits..

1. I'm not sure about "There will be no 32-bit desktop CPUs". ARM is currently 32-bit; and has declared little interest in 64-bit; for now. That doesn't fit too well with "Desktop" in your description; but I also think in 5-10 years the landscape of the type of devices we are writing software will drastically change as well. Tablets can't be ignored; people will want C# and Java apps to run on them, considering Microsoft officially ported Windows 8 to ARM.

2. If you want to start using long; go ahead. There is no reason not to. If we are only looking at the CPU (ignoring storage size), and making assumptions we are on an x86-64 architecture, then it doesn't make much difference.

3. Assuming that we are sticking with the x86 architecture; that's true as well. You may end up with a slightly larger stack; depending on whatever framework you are using.