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Update compound-types.md #139

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Feb 28, 2024
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Update compound-types.md #139

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Update compound-types.md
jonathanpallant Feb 28, 2024
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Update training-slides/src/compound-types.md
miguelraz Feb 28, 2024
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Update training-slides/src/compound-types.md
miguelraz Feb 28, 2024
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18 changes: 16 additions & 2 deletions training-slides/src/compound-types.md
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Expand Up @@ -13,6 +13,11 @@ struct Point {
}
```

Note:

The fields may not be laid out in memory in the order they are written (unless
you ask the compiler to ensure that they are).

## Construction

- there is no partial initialization
Expand Down Expand Up @@ -143,8 +148,17 @@ fn main() {

## Enums with Values

- An enum is the same size, no matter which variant is picked
- It will be the size of the largest variant
- An enum value is the same size, no matter which variant is picked
- It will be the size of the largest variant (plus a tag)

Note:

The tag in an enum specifies which variant is currently valid, and is stored as the
smallest integer the compiler can get away with - it depends how many variants you
have. Of course, if none of the variants have any data, the enum is *just* the tag.

If you have a C background, you can think of this as being a `struct` containing an `int`
and a `union`.

## Doing a `match` on an `enum`

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