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