fn main(){
    println!("Hello, World!");
    println!("{}, {}!","Hello","World");
    println!("{0}, {1}!","Hello","World");
    println!("{h}, {w}!",h="Hello", w="World");
    let y = String::from("Hello, ") + "world!";
    println!("{}",y);
}

得嘞，今天算是开了rust之旅了。