94 lines
2.3 KiB
Rust
94 lines
2.3 KiB
Rust
use std::f32::consts::E;
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#[derive(Debug, PartialEq, Eq)]
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enum DivisionError {
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// Example: 42 / 0
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DivideByZero,
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// Only case for `i64`: `i64::MIN / -1` because the result is `i64::MAX + 1`
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IntegerOverflow,
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// Example: 5 / 2 = 2.5
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NotDivisible,
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}
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// Otherwise, return a suitable error.
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fn divide(a: i64, b: i64) -> Result<i64, DivisionError> {
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if b == 0 {
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return Err(DivisionError::DivideByZero)
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}
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match a.checked_rem(b) {
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None => {
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Err(DivisionError::IntegerOverflow)
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}
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Some(0) => {
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let division = a.checked_div(b);
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if let Some(result) = division {
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Ok(result)
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} else {
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Err(DivisionError::IntegerOverflow)
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}
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},
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Some(_) => {
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Err(DivisionError::NotDivisible)
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}
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}
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}
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// Desired output: `Ok([1, 11, 1426, 3])`
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fn result_with_list() -> Result<Vec<i64>, DivisionError> {
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let numbers = [27, 297, 38502, 81];
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let division_results = numbers.into_iter().map(|n| divide(n, 27));
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Ok(division_results.map(|i| {
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i.unwrap()
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}).collect::<Vec<i64>>())
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}
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// Desired output: `[Ok(1), Ok(11), Ok(1426), Ok(3)]`
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fn list_of_results() -> Vec<Result<i64, DivisionError>>{
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let numbers = [27, 297, 38502, 81];
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let division_results = numbers.into_iter().map(|n| divide(n, 27));
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division_results.collect()
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}
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fn main() {
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// You can optionally experiment here.
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_success() {
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assert_eq!(divide(81, 9), Ok(9));
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}
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#[test]
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fn test_divide_by_0() {
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assert_eq!(divide(81, 0), Err(DivisionError::DivideByZero));
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}
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#[test]
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fn test_integer_overflow() {
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assert_eq!(divide(i64::MIN, -1), Err(DivisionError::IntegerOverflow));
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}
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#[test]
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fn test_not_divisible() {
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assert_eq!(divide(81, 6), Err(DivisionError::NotDivisible));
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}
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#[test]
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fn test_divide_0_by_something() {
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assert_eq!(divide(0, 81), Ok(0));
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}
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#[test]
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fn test_result_with_list() {
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assert_eq!(result_with_list().unwrap(), [1, 11, 1426, 3]);
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}
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#[test]
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fn test_list_of_results() {
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assert_eq!(list_of_results(), [Ok(1), Ok(11), Ok(1426), Ok(3)]);
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}
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}
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