Trait std::fmt::Octal

o 格式。

pub trait Octal {
    // Required method
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}

Octal trait 应该将其输出格式化为 base-8 中的数字。

对于原始有符号整数 (i8 至 i128 和 isize)，负值的格式设置为二进制补码表示形式。

备用标志 # 在输出前面添加 0o。

i32 的基本用法：

let x = 42; // 42 是八进制的 '52'

assert_eq!(format!("{x:o}"), "52");
assert_eq!(format!("{x:#o}"), "0o52");

assert_eq!(format!("{:o}", -16), "37777777760");

在类型上实现 Octal：

use std::fmt;

struct Length(i32);

impl fmt::Octal for Length {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let val = self.0;

        fmt::Octal::fmt(&val, f) // 委托给 i32 的实现
    }
}

let l = Length(9);

assert_eq!(format!("l as octal is: {l:o}"), "l as octal is: 11");

assert_eq!(format!("l as octal is: {l:#06o}"), "l as octal is: 0o0011");

Required Methods

fmt

使用给定的格式化程序格式化该值。

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Implementors

impl Octal for i8

impl Octal for i16

impl Octal for i32

impl Octal for i64

impl Octal for i128

impl Octal for isize

impl Octal for u8

impl Octal for u16

impl Octal for u32

impl Octal for u64

impl Octal for u128

impl Octal for usize

impl Octal for NonZeroI8

impl Octal for NonZeroI16

impl Octal for NonZeroI32

impl Octal for NonZeroI64

impl Octal for NonZeroI128

impl Octal for NonZeroIsize

impl Octal for NonZeroU8

impl Octal for NonZeroU16

impl Octal for NonZeroU32

impl Octal for NonZeroU64

impl Octal for NonZeroU128

impl Octal for NonZeroUsize

impl<T> Octal for &T

impl<T> Octal for &T
where
  T: Octal + ?Sized,

impl<T> Octal for &mut T

impl<T> Octal for &mut T
where
  T: Octal + ?Sized,

impl<T> Octal for Saturating<T>

impl<T> Octal for Saturating<T>
where
  T: Octal,

impl<T> Octal for Wrapping<T>

impl<T> Octal for Wrapping<T>
where
  T: Octal,