Implement the classic method for composing secret messages called a square code.
Given an English text, output the encoded version of that text.
First, the input is normalized: the spaces and punctuation are removed from the English text and the message is downcased.
Then, the normalized characters are broken into rows. These rows can be regarded as forming a rectangle when printed with intervening newlines.
For example, the sentence
"If man was meant to stay on the ground, god would have given us roots."
is normalized to:
"ifmanwasmeanttostayonthegroundgodwouldhavegivenusroots"
The plaintext should be organized in to a rectangle. The size of the
rectangle (r x c
) should be decided by the length of the message,
such that c >= r
and c - r <= 1
, where c
is the number of columns
and r
is the number of rows.
Our normalized text is 54 characters long, dictating a rectangle with
c = 8
and r = 7
:
"ifmanwas"
"meanttos"
"tayonthe"
"groundgo"
"dwouldha"
"vegivenu"
"sroots "
The coded message is obtained by reading down the columns going left to right.
The message above is coded as:
"imtgdvsfearwermayoogoanouuiontnnlvtwttddesaohghnsseoau"
Output the encoded text in chunks that fill perfect rectangles (r X c)
,
with c
chunks of r
length, separated by spaces. For phrases that are
n
characters short of the perfect rectangle, pad each of the last n
chunks with a single trailing space.
"imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn sseoau "
Notice that were we to stack these, we could visually decode the ciphertext back in to the original message:
"imtgdvs"
"fearwer"
"mayoogo"
"anouuio"
"ntnnlvt"
"wttddes"
"aohghn "
"sseoau "
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.
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
cargo fmt
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.
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J Dalbey's Programming Practice problems http://users.csc.calpoly.edu/~jdalbey/103/Projects/ProgrammingPractice.html
It's possible to submit an incomplete solution so you can see how others have completed the exercise.