# Hello World

Greet the user by name, or by saying "Hello, World!" if no name is given.

["Hello, World!"](http://en.wikipedia.org/wiki/%22Hello,_world!%22_program) is
the traditional first program for beginning programming in a new language.

**Note:** You can skip this exercise by running:

    exercism skip $TRACK_ID hello-world

## Specification

Write a `Hello World!` function that can greet someone given their name.  The
function should return the appropriate greeting.

For an input of "Alice", the response should be "Hello, Alice!".

If a name is not given, the response should be "Hello, World!"

## Test-Driven Development

As programmers mature, they eventually want to test their code.

Here at Exercism we simulate [Test-Driven
Development](http://en.wikipedia.org/wiki/Test-driven_development) (TDD), where
you write your tests before writing any functionality. The simulation comes in
the form of a pre-written test suite, which will signal that you have solved
the problem.

It will also provide you with a safety net to explore other solutions without
breaking the functionality.

### A typical TDD workflow on Exercism:

1. Run the test file and pick one test that's failing.
2. Write some code to fix the test you picked.
3. Re-run the tests to confirm the test is now passing.
4. Repeat from step 1.
5. Submit your solution (`exercism submit /path/to/file`)

## Instructions

Submissions are encouraged to be general, within reason. Having said that, it's
also important not to over-engineer a solution.

It's important to remember that the goal is to make code as expressive and
readable as we can. However, solutions to the hello-world exercise will not be
reviewed by a person, but by rikki- the robot, who will offer an encouraging
word.

## Rust Installation

Refer to the [exercism help page][help-page] for Rust installation and learning
resources.

## Writing the Code

Execute the tests with:

```bash
$ cargo test
```

All but the first test have been ignored.  After you get the first test to
pass, remove the ignore flag (`#[ignore]`) from the next test and get the tests
to pass again.  The test file is located in the `tests` directory.   You can
also remove the ignore flag from all the tests to get them to run all at once
if you wish.

Make sure to read the [Crates and Modules](https://doc.rust-lang.org/stable/book/crates-and-modules.html) chapter if you
haven't already, it will help you with organizing your files.

## Feedback, Issues, Pull Requests

The [exercism/xrust](https://github.com/exercism/xrust) 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](https://github.com/orgs/exercism/teams/rust) are happy to help!

If you want to know more about Exercism, take a look at the [contribution guide](https://github.com/exercism/x-common/blob/master/CONTRIBUTING.md).

[help-page]: http://exercism.io/languages/rust
[crates-and-modules]: http://doc.rust-lang.org/stable/book/crates-and-modules.html

## Source

This is an exercise to introduce users to using Exercism [http://en.wikipedia.org/wiki/%22Hello,_world!%22_program](http://en.wikipedia.org/wiki/%22Hello,_world!%22_program)

## Submitting Incomplete Problems
It's possible to submit an incomplete solution so you can see how others have completed the exercise.