# Trait alloc::fmt::UpperHex

1.0.0 · source ·

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

Expand description

`X` formatting.

The `UpperHex` trait should format its output as a number in hexadecimal, with `A` through `F` in upper case.

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

The alternate flag, `#`, adds a `0x` 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 '2A' in hex

    assert_eq!(format!("{x:X}"), "2A");
    assert_eq!(format!("{x:#X}"), "0x2A");

    assert_eq!(format!("{:X}", -16), "FFFFFFF0");

Run

Implementing `UpperHex` on a type:

    use std::fmt;

    struct Length(i32);

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

            fmt::UpperHex::fmt(&val, f) // delegate to i32's implementation
        }
    }

    let l = Length(i32::MAX);

    assert_eq!(format!("l as hex is: {l:X}"), "l as hex is: 7FFFFFFF");

    assert_eq!(format!("l as hex is: {l:#010X}"), "l as hex is: 0x7FFFFFFF");

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 UpperHex for i8

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### impl UpperHex for i16

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### impl UpperHex for i32

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### impl UpperHex for i64

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### impl UpperHex for i128

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### impl UpperHex for isize

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### impl UpperHex for u8

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### impl UpperHex for u16

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### impl UpperHex for u32

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### impl UpperHex for u64

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### impl UpperHex for u128

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### impl UpperHex for usize

1.34.0 · source§

### impl UpperHex for NonZeroI8

1.34.0 · source§

### impl UpperHex for NonZeroI16

1.34.0 · source§

### impl UpperHex for NonZeroI32

1.34.0 · source§

### impl UpperHex for NonZeroI64

1.34.0 · source§

### impl UpperHex for NonZeroI128

1.34.0 · source§

### impl UpperHex for NonZeroIsize

1.28.0 · source§

### impl UpperHex for NonZeroU8

1.28.0 · source§

### impl UpperHex for NonZeroU16

1.28.0 · source§

### impl UpperHex for NonZeroU32

1.28.0 · source§

### impl UpperHex for NonZeroU64

1.28.0 · source§

### impl UpperHex for NonZeroU128

1.28.0 · source§

### impl UpperHex for NonZeroUsize

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

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

1.74.0 · source§

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

1.11.0 · source§

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