method usize.checked_sub

Checked subtraction: the difference, or none on overflow.

Example:

fn main() io {
  let max: usize = 18446744073709551615
  let min: usize = 0
  print("{min.checked_sub(1)}")
  print("{(min + 1).checked_sub(1)}")
}

none
0

pub(api) fn checked_sub(o: usize) -> usize?

Complexity. O(1).

Since. 1.0.0-beta

Parameters

Returns

usize?

Effects

none declared (pure unless the body says otherwise)

Defined in: std/core/numbers.oxl:3339