49 lines
1.3 KiB
Rust
49 lines
1.3 KiB
Rust
fn main() {
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// You can optionally experiment here.
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}
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#[cfg(test)]
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mod tests {
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#[test]
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fn simple_option() {
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let target = "rustlings";
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let optional_target = Some(target);
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// TODO: Make this an if-let statement whose value is `Some`.
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// word = optional_target {
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// assert_eq!(word, target);
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// }
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if let Some(word) = optional_target {
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assert_eq!(word, target);
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}
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}
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#[test]
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fn layered_option() {
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let range = 10;
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let mut optional_integers: Vec<Option<i8>> = vec![None];
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for i in 1..=range {
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optional_integers.push(Some(i));
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}
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let mut cursor = range;
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// TODO: Make this a while-let statement. Remember that `Vec::pop()`
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// adds another layer of `Option`. You can do nested pattern matching
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// in if-let and while-let statements.
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while let Some(integer) = optional_integers.pop() {
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if let Some(integer_value) = integer {
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println!("integer_value (left): {}, cursor (right): {}", integer_value, cursor);
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assert_eq!(integer_value, cursor);
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cursor -= 1;
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} else {
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println!("None value, cursor: {}", cursor);
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}
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}
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assert_eq!(cursor, 0);
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}
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}
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