走进 Rust:打印结构体字段
Rust About 1,017 words定义结构体
struct Rectangle {
width: u32,
height: u32,
}
打印结构体
使用{}
打印会报错。
fn main() {
let rect1 = Rectangle { width: 30, height: 50 };
println!("rect1 is {}", rect1);
}
提示信息:
= help: the trait `std::fmt::Display` is not implemented for `Rectangle`
= note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
使用{:?}
或{:#?}
打印结构体中的字段信息。
fn main() {
let rect1 = Rectangle { width: 30, height: 50 };
println!("rect1 is {:?}", rect1);
}
提示信息:
= help: the trait `std::fmt::Debug` is not implemented for `Rectangle`
= note: add `#[derive(Debug)]` or manually implement `std::fmt::Debug`
结构体上增加#[derive(Debug)]
#[derive(Debug)]
struct Rectangle {
width: u32,
height: u32,
}
fn main() {
let rect1 = Rectangle { width: 30, height: 50 };
println!("rect1 print by :?, {:?}", rect1);
println!("rect1 print by :#?, {:#?}", rect1);
}
输出:
rect1 print by :?, Rectangle { width: 30, height: 50 }
rect1 print by :#?, Rectangle {
width: 30,
height: 50,
}
Views: 8,016 · Posted: 2020-07-09
————        END        ————
Give me a Star, Thanks:)
https://github.com/fendoudebb/LiteNote扫描下方二维码关注公众号和小程序↓↓↓
Loading...