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rustlings/solutions/16_lifetimes/lifetimes1.rs
2024-06-27 13:24:21 +02:00

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723 B
Rust

// The Rust compiler needs to know how to check whether supplied references are
// valid, so that it can let the programmer know if a reference is at risk of
// going out of scope before it is used. Remember, references are borrows and do
// not own their own data. What if their owner goes out of scope?
fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
// ^^^^ ^^ ^^ ^^
if x.len() > y.len() {
x
} else {
y
}
}
fn main() {
// You can optionally experiment here.
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_longest() {
assert_eq!(longest("abcd", "123"), "abcd");
assert_eq!(longest("abc", "1234"), "1234");
}
}