92 lines
2.6 KiB
Rust
92 lines
2.6 KiB
Rust
// iterators3.rs
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// This is a bigger exercise than most of the others! You can do it!
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// Here is your mission, should you choose to accept it:
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// 1. Complete the divide function to get the first four tests to pass.
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// 2. Get the remaining tests to pass by completing the result_with_list and
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// list_of_results functions.
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// Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a hint.
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#[derive(Debug, PartialEq, Eq)]
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pub enum DivisionError {
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NotDivisible(NotDivisibleError),
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DivideByZero,
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}
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#[derive(Debug, PartialEq, Eq)]
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pub struct NotDivisibleError {
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dividend: i32,
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divisor: i32,
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}
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// Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
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// Otherwise, return a suitable error.
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pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
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if a.checked_div(b).is_none() {
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Err(DivisionError::DivideByZero)
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} else if a.checked_rem(b) != Some(0) {
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Err(DivisionError::NotDivisible(NotDivisibleError {dividend: a, divisor: b}))
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} else {
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Ok(a / b)
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}
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}
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// Complete the function and return a value of the correct type so the test passes.
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// Desired output: Ok([1, 11, 1426, 3])
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fn result_with_list() -> Result<Vec<i32>, DivisionError> {
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let numbers = vec![27, 297, 38502, 81];
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let division_results = numbers.into_iter().map(|n| divide(n, 27).unwrap());
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Ok(Vec::from_iter(division_results))
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}
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// Complete the function and return a value of the correct type so the test passes.
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// Desired output: [Ok(1), Ok(11), Ok(1426), Ok(3)]
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fn list_of_results() -> Vec<Result<i32, DivisionError>> {
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let numbers = vec![27, 297, 38502, 81];
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let division_results = numbers.into_iter().map(|n| divide(n, 27));
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Vec::from_iter(division_results)
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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_not_divisible() {
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assert_eq!(
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divide(81, 6),
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Err(DivisionError::NotDivisible(NotDivisibleError {
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dividend: 81,
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divisor: 6
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}))
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);
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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_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!(format!("{:?}", result_with_list()), "Ok([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!(
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format!("{:?}", list_of_results()),
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"[Ok(1), Ok(11), Ok(1426), Ok(3)]"
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);
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}
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}
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