Reverse a string
For example: input: "cool" output: "looc"
Test your function on this string: uüu
and see what happens. Try to write a function that properly
reverses this string. Hint: grapheme clusters
To get the bonus test to run, remove the ignore flag (#[ignore]
) from the
last test, and execute the tests with:
$ cargo test --features grapheme
Refer to the exercism help page for Rust installation and learning resources.
Execute the tests with:
$ cargo test
All but the first test have been ignored. After you get the first test to
pass, open the tests source file which is located in the tests
directory
and remove the #[ignore]
flag from the next test and get the tests to pass
again. Each separate test is a function with #[test]
flag above it.
Continue, until you pass every test.
If you wish to run all tests without editing the tests source file, use:
$ cargo test -- --ignored
To run a specific test, for example some_test
, you can use:
$ cargo test some_test
If the specific test is ignored use:
$ cargo test some_test -- --ignored
To learn more about Rust tests refer to the online test documentation
Make sure to read the Modules chapter if you haven't already, it will help you with organizing your files.
The exercism/rust repository on GitHub is the home for all of the Rust exercises. If you have feedback about an exercise, or want to help implement new exercises, head over there and create an issue. Members of the rust track team are happy to help!
If you want to know more about Exercism, take a look at the contribution guide.
Introductory challenge to reverse an input string https://medium.freecodecamp.org/how-to-reverse-a-string-in-javascript-in-3-different-ways-75e4763c68cb
It's possible to submit an incomplete solution so you can see how others have completed the exercise.
//! Tests for reverse-string
//!
//! Generated by [script][script] using [canonical data][canonical-data]
//!
//! [script]: https://github.com/exercism/rust/blob/b829ce2/bin/init_exercise.py
//! [canonical-data]: https://raw.githubusercontent.com/exercism/problem-specifications/master/exercises/reverse-string/canonical_data.json
use reverse_string::*;
/// Process a single test case for the property `reverse`
fn process_reverse_case(input: &str, expected: &str) {
assert_eq!(&reverse(input), expected)
}
#[test]
/// empty string
fn test_an_empty_string() {
process_reverse_case("", "");
}
#[test]
#[ignore]
/// a word
fn test_a_word() {
process_reverse_case("robot", "tobor");
}
#[test]
#[ignore]
/// a capitalized word
fn test_a_capitalized_word() {
process_reverse_case("Ramen", "nemaR");
}
#[test]
#[ignore]
/// a sentence with punctuation
fn test_a_sentence_with_punctuation() {
process_reverse_case("I'm hungry!", "!yrgnuh m'I");
}
#[test]
#[ignore]
/// a palindrome
fn test_a_palindrome() {
process_reverse_case("racecar", "racecar");
}
#[test]
#[ignore]
/// wide characters
fn test_wide_characters() {
process_reverse_case("子猫", "猫子");
}
#[test]
#[ignore]
#[cfg(feature = "grapheme")]
/// grapheme clusters
fn test_grapheme_clusters() {
process_reverse_case("uüu", "uüu");
}
use unicode_segmentation::UnicodeSegmentation;
// https://stackoverflow.com/a/27996791
pub fn reverse(input: &str) -> String {
input
.graphemes(true)
.rev()
.flat_map(|g| g.chars())
.collect::<String>()
}
A huge amount can be learned from reading other people’s code. This is why we wanted to give exercism users the option of making their solutions public.
Here are some questions to help you reflect on this solution and learn the most from it.
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