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147 lines
2.4 KiB
Rust
147 lines
2.4 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. Uncomment the last two tests and get them to pass by filling in
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// values for `x` using `division_results`.
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// Scroll down for a minor hint for part 2, and scroll down further for
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// a major hint.
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// Have fun :-)
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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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// This function should calculate `a` divided by `b` if `a` is
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// evenly divisible by b.
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// Otherwise, it should return a suitable error.
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pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {}
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#[cfg(test)]
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mod tests {
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use super::*;
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// Tests that verify your `divide` function implementation
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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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// Iterator exercises using your `divide` function
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/*
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#[test]
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fn result_with_list() {
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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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let x //... Fill in here!
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assert_eq!(format!("{:?}", x), "Ok([1, 11, 1426, 3])");
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}
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#[test]
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fn list_of_results() {
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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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let x //... Fill in here!
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assert_eq!(format!("{:?}", x), "[Ok(1), Ok(11), Ok(1426), Ok(3)]");
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}
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*/
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}
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// Minor hint: In each of the two cases in the match in main, you can create x with either
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// a 'turbofish' or by hinting the type of x to the compiler. You may try both.
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// Major hint: Have a look at the Iter trait and at the explanation of its collect function.
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// Especially the part about Result is interesting.
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