rust 范型

fn testOption(){
    let i :Option<i32> = Some(1);
    let s :Option<&str> = Some("hello");
    let c :Option<char> = Some('A');
    let o :Option<u32> = None;
    prt(i);
    prt(s);
    prt(c);
    prt(o);
}

1
"hello"
'A'
nothing
1