pub trait Binary {
// Required method
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}Expand description
b formatting.
The Binary trait should format its output as a number in binary.
For primitive signed integers (i8 to i128, and isize),
negative values are formatted as the two’s complement representation.
The alternate flag, #, adds a 0b 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 '101010' in binary
assert_eq!(format!("{x:b}"), "101010");
assert_eq!(format!("{x:#b}"), "0b101010");
assert_eq!(format!("{:b}", -16), "11111111111111111111111111110000");Implementing Binary on a type:
use std::fmt;
struct Length(i32);
impl fmt::Binary for Length {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let val = self.0;
fmt::Binary::fmt(&val, f) // delegate to i32's implementation
}
}
let l = Length(107);
assert_eq!(format!("l as binary is: {l:b}"), "l as binary is: 1101011");
assert_eq!(
// Note that the `0b` prefix added by `#` is included in the total width, so we
// need to add two to correctly display all 32 bits.
format!("l as binary is: {l:#034b}"),
"l as binary is: 0b00000000000000000000000001101011"
);Required Methods§
1.36.0 · Sourcefn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
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.