Grains

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:

• how many grains were on a given square, and
• the total number of grains on the chessboard

For bonus points

Did you get the tests passing and the code clean? If you want to, these are some additional things you could try:

• Optimize for speed.
• Optimize for readability.

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?

Setup

Follow the setup instructions for Crystal here:

http://exercism.io/languages/crystal

More help installing can be found here:

http://crystal-lang.org/docs/installation/index.html

Making the Test Suit Pass

Execute the tests with:

$ crystal spec

In each test suite all but the first test have been skipped.

Once you get a test passing, you can unskip the next one by changing pending to it.

Source

JavaRanch Cattle Drive, exercise 6 http://www.javaranch.com/grains.jsp

Submitting Incomplete Solutions

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