Boolean how many bytes

From the description, it mentions that the size of the boolean value is not precisely defined. This indicates that there is some uncertainty about its size in different conditions. Let's check further. On Stackoverflow , someone did a testing to check the size of boolean in an array. From the result, it looks like that int takes 4x size of boolean, since int is 4 bytes.

Does this mean that boolean is one byte? Nawaz Nawaz k gold badges silver badges bronze badges. Steve : oops I overlooked that. Removed int and char from my post. That's why bit fields exist as a special case: the bitfield members of a struct aren't required to be separately addressable, so they can be smaller than a char although the whole struct still can't be.

Steve Jessop : that seems interesting. Obviously sizeof bool can't be 0. Show 1 more comment. Not sure I would agree that bitwise operations are slow. It is typically the implementation of the bitwise operations that are slow. At the machine level they are quite fast.

If you put another boolean in, it will take another byte. Yet, if you push another boolean, it won't take any extra bytes because it uses the "free" bits in the last byte — Pedro Loureiro. The bit vectors do not create bit-sized allocations.

It is not possible to allocate a single bit. Reading a single bit in a bit vector requires three operations: shift, and, and another shift again. Writing is two. Whereas individual bytes can be accessed with a single one. Show 2 more comments.

Jay Jay Except when dealing with Flags. Things like Setting multiple options on something Atomix: I almost never do this anymore.

If I need two flags, I create two boolean fields. I wouldn't rule out the possibility of cases where packing flags like that is better for some reason, but it's no longer necessary to save memory like it used to be. Actually, it is quite worth your trouble to pack bits, if you want your computation to be fast - on that large amount of data you store in memory.

Packing booleans isn't just for smaller storage - it means you can read your boolean input arrays 8 times faster in terms of bandwidth as when they're unpacked, and that's often quite significant.

Also, you can use bit operations, like popc population count which speeds up your work on the CPU itself. Truly huge number of booleans is what you work with every day if you do: DBMSes, machine learning, scientific simulations, and a whole host of other things. And - just working on them means copying them - from memory into cache. A million bools is nothing, think billions. PeterCordes Yes, absolutely, if I had a set of booleans that were logically the "same idea" so that I naturally think of them as an "array" in some sense, and if I'm then going to mask or filter them or otherwise perform bitwise operations on them, then packing them into bytes might make good sense.

As I said earlier, I'm hard pressed to think of the last time I worked on an application where those conditions applied, but you give a couple of good examples, and I'm sure with a little imagination one could think of others. Show 15 more comments. Paul Sasik Paul Sasik Because a byte is the smallest addressible unit in the language. Toon Krijthe You can use bit fields to get integers of sub size.

Try it Yourself » Int The int data type can store whole numbers from to In general, and in our tutorial, the int data type is the preferred data type when we create variables with a numeric value. The long data type can store whole numbers from to This is used when int is not large enough to store the value. Note that you should end the value with an "L":. You should use a floating point type whenever you need a number with a decimal, such as 9.

The float data type can store fractional numbers from 3. Note that you should end the value with an "f":. The double data type can store fractional numbers from 1. Note that you should end the value with a "d":. The precision of a floating point value indicates how many digits the value can have after the decimal point. The precision of float is only six or seven decimal digits, while double variables have a precision of about 15 digits.

Therefore it is safer to use double for most calculations. A boolean data type is declared with the boolean keyword and can only take the values true or false :.

Boolean values are mostly used for conditional testing, which you will learn more about in a later chapter. The char data type is used to store a single character.

The character must be surrounded by single quotes, like 'A' or 'c':. The String data type is used to store a sequence of characters text.