Trait core::fmt::Octal

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

o formatting.

The Octal trait should format its output as a number in base-8.

For primitive signed integers (i8 to i128, and isize), negative values are formatted as the two’s complement representation.

The alternate flag, #, adds a 0o in front of the output.

For more information on formatters, see the module-level documentation.

§Examples

Basic usage with i32:

let x = 42; // 42 is '52' in octal

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

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

Implementing Octal on a type:

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) // delegate to i32's implementation
    }
}

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§

1.0.0 · source

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

Formats the value using the given formatter.

§Errors

This function should return Err if, and only if, the provided Formatter returns Err. String formatting is considered an infallible operation; this function only returns a Result because writing to the underlying stream might fail and it must provide a way to propagate the fact that an error has occurred back up the stack.

Implementors§

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impl Octal for i8

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impl Octal for i16

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impl Octal for i32

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impl Octal for i64

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impl Octal for i128

1.0.0 · source§

impl Octal for isize

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impl Octal for u8

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impl Octal for u16

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impl Octal for u32

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impl Octal for u64

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impl Octal for u128

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impl Octal for usize

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impl<T> Octal for NonZero<T>

1.74.0 · source§

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

1.11.0 · source§

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

1.0.0 · source§

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

1.0.0 · source§

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