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#[derive(Debug, PartialEq, Eq)]
enum DivisionError {
// Example: 42 / 0
DivideByZero,
// Only case for `i64`: `i64::MIN / -1` because the result is `i64::MAX + 1`
IntegerOverflow,
// Example: 5 / 2 = 2.5
NotDivisible,
}
// TODO: Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
// Otherwise, return a suitable error.
fn divide(a: i64, b: i64) -> Result<i64, DivisionError> {
todo!();
}
// TODO: Add the correct return type and complete the function body.
// Desired output: `Ok([1, 11, 1426, 3])`
fn result_with_list() {
let numbers = [27, 297, 38502, 81];
let division_results = numbers.into_iter().map(|n| divide(n, 27));
}
// TODO: Add the correct return type and complete the function body.
// Desired output: `[Ok(1), Ok(11), Ok(1426), Ok(3)]`
fn list_of_results() {
let numbers = [27, 297, 38502, 81];
let division_results = numbers.into_iter().map(|n| divide(n, 27));
}
fn main() {
// You can optionally experiment here.
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_success() {
assert_eq!(divide(81, 9), Ok(9));
assert_eq!(divide(81, -1), Ok(-81));
assert_eq!(divide(i64::MIN, i64::MIN), Ok(1));
}
#[test]
fn test_divide_by_0() {
assert_eq!(divide(81, 0), Err(DivisionError::DivideByZero));
}
#[test]
fn test_integer_overflow() {
assert_eq!(divide(i64::MIN, -1), Err(DivisionError::IntegerOverflow));
}
#[test]
fn test_not_divisible() {
assert_eq!(divide(81, 6), Err(DivisionError::NotDivisible));
}
#[test]
fn test_divide_0_by_something() {
assert_eq!(divide(0, 81), Ok(0));
}
#[test]
fn test_result_with_list() {
assert_eq!(result_with_list().unwrap(), [1, 11, 1426, 3]);
}
#[test]
fn test_list_of_results() {
assert_eq!(list_of_results(), [Ok(1), Ok(11), Ok(1426), Ok(3)]);
}
}
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