Calculate the number of grains of wheat on a chessboard given that the number on each square doubles.
There once was a wise servant who saved the life of a prince. The king promised to pay whatever the servant could dream up. Knowing that the king loved chess, the servant told the king he would like to have grains of wheat. One grain on the first square of a chess board, with the number of grains doubling on each successive square.
There are 64 squares on a chessboard (where square 1 has one grain, square 2 has two grains, and so on).
Write code that shows:
Did you get the tests passing and the code clean? If you want to, these are some additional things you could try:
Then please share your thoughts in a comment on the submission. Did this experiment make the code better? Worse? Did you learn anything from it?
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
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 ignored 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.
After you have solved the exercise, please consider using the additional utilities, described in the installation guide, to further refine your final solution.
To format your solution, inside the solution directory use
To see, if your solution contains some common ineffective use cases, inside the solution directory use
cargo clippy --all-targets
Generally you should submit all files in which you implemented your solution (
src/lib.rs in most cases). If you are using any external crates, please consider submitting the
Cargo.toml file. This will make the review process faster and clearer.
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.
JavaRanch Cattle Drive, exercise 6 http://www.javaranch.com/grains.jsp
It's possible to submit an incomplete solution so you can see how others have completed the exercise.