x formatting.
The LowerHex trait should format its output as a number in hexadecimal, with a through f
in lower 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.
Basic usage with i32:
let x = 42; 
assert_eq!(format!("{:x}", x), "2a");
assert_eq!(format!("{:#x}", x), "0x2a");
assert_eq!(format!("{:x}", -16), "fffffff0");Run
Implementing LowerHex on a type:
use std::fmt;
struct Length(i32);
impl fmt::LowerHex for Length {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let val = self.0;
        write!(f, "{:x}", val) 
    }
}
let l = Length(9);
println!("l as hex is: {:x}", l);Run
        Formats the value using the given formatter.
 | impl LowerHex for i8 | [src] | 
| impl LowerHex for i16 | [src] | 
| impl LowerHex for i32 | [src] | 
| impl LowerHex for i64 | [src] | 
| impl LowerHex for i128 | [src] | 
| impl LowerHex for isize | [src] | 
| impl LowerHex for u8 | [src] | 
| impl LowerHex for u16 | [src] | 
| impl LowerHex for u32 | [src] | 
| impl LowerHex for u64 | [src] | 
| impl LowerHex for u128 | [src] | 
| impl LowerHex for usize | [src] |