mirror of
https://github.com/rust-lang/rust.git
synced 2024-12-02 19:53:46 +00:00
28 lines
609 B
Rust
28 lines
609 B
Rust
//@ run-pass
|
|
|
|
use std::collections::HashMap;
|
|
|
|
fn process_or_insert_default(map: &mut HashMap<usize, String>, key: usize) {
|
|
match map.get_mut(&key) {
|
|
Some(value) => {
|
|
process(value);
|
|
}
|
|
None => {
|
|
map.insert(key, "".to_string());
|
|
}
|
|
}
|
|
}
|
|
|
|
fn process(x: &str) {
|
|
assert_eq!(x, "Hello, world");
|
|
}
|
|
|
|
fn main() {
|
|
let map = &mut HashMap::new();
|
|
map.insert(22, format!("Hello, world"));
|
|
map.insert(44, format!("Goodbye, world"));
|
|
process_or_insert_default(map, 22);
|
|
process_or_insert_default(map, 66);
|
|
assert_eq!(map[&66], "");
|
|
}
|