# Trait alloc::fmt::Octal

1.0.0 · source ·

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

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");

Run

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");

Run

## Required Methods§

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

Formats the value using the given formatter.

## 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

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### 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

1.34.0 · source§

### impl Octal for NonZeroI8

1.34.0 · source§

### impl Octal for NonZeroI16

1.34.0 · source§

### impl Octal for NonZeroI32

1.34.0 · source§

### impl Octal for NonZeroI64

1.34.0 · source§

### impl Octal for NonZeroI128

1.34.0 · source§

### impl Octal for NonZeroIsize

1.28.0 · source§

### impl Octal for NonZeroU8

1.28.0 · source§

### impl Octal for NonZeroU16

1.28.0 · source§

### impl Octal for NonZeroU32

1.28.0 · source§

### impl Octal for NonZeroU64

1.28.0 · source§

### impl Octal for NonZeroU128

1.28.0 · source§

### impl Octal for NonZeroUsize

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

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

1.74.0 · source§

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

1.11.0 · source§

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