use std::collections::HashSet;
fn main() {
let mut hs = HashSet::new();
hs.insert("Rust");
hs.insert("C");
hs.insert("C");
hs.insert("C++");
hs.insert("Python");
hs.insert("Java");
println!("{:?}", hs);
hs.remove(&"Java");
println!("{:?}", hs);
}
/*
run:
{"Java", "Rust", "C", "C++", "Python"}
{"Rust", "C", "C++", "Python"}
*/