Please explain uint32_t and 0x1

Question

I found a couple of lines in apples sample codes for SpriteKit ``` static const uint32_t missileCategory = 0x1 << 0; ``` I know what `static const` is but what is an `uint32_t` and what does `0x1 << 0` mean? is it some sort of hex?

Accepted Answer

`<<` is bitwise left shift (multiply by 2) operator.

`<< 0` is the same as `*1`

So equivalent statement would be:

```
static const uint32_t missileCategory  =  0x1;
```

I wrote more on this here.

For example:

`0x1 << 4` would return `0x10`.

Looking at it binary:

```
00000001 << 4 = 00010000
```

Decimaly speaking this would mean `1 * 2 * 2 * 2 * 2` or `1 * 2^4`

And since this is `uint32_t` value it would actualy be

```
0x00000010
```

Please explain uint32_t and 0x1 << 0 in Apple SpriteKit sample code

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