a56f648cce
Expected result is updated to better showcase the difference between - a valid result with no ice-creams `Some(0)`, and - an invalid result `None`. |
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| .. | ||
| options1.rs | ||
| options2.rs | ||
| options3.rs | ||
| README.md | ||
Options
Type Option represents an optional value: every Option is either Some and contains a value, or None, and does not. Option types are very common in Rust code, as they have a number of uses:
- Initial values
- Return values for functions that are not defined over their entire input range (partial functions)
- Return value for otherwise reporting simple errors, where None is returned on error
- Optional struct fields
- Struct fields that can be loaned or "taken"
- Optional function arguments
- Nullable pointers
- Swapping things out of difficult situations