5708c3d85a
Removed generator-exercises folder as it breaks jest-codemods run jest-codemods on .spec.js files, move generator-exercises back in Change references from Jasmine to Jest in main readme Update README with Jest specific language. Update some spec files with new syntax update tests, multiple exercises .gitignore: Added package-lock.json, package.json that were used when I ran code-blocks over the tests. Standardised function declaration calls across exercises fix typo in caesar.spec.js Ignoring package-lock.json, package.json Backtrack on .gitignore modification, add instructions to readme move files from testing repo to this repo Typo fixes, remove duplicate exercise folder Remove solution from non-solution branch Minor grammatical fixes added trailing semicolon to all function and module exports Fix words caught by search/replace action. remove doubled semicolon. Correct words caught by search/replace action. Add missing semicolon. Add .DS_Store to .gitignore multiple files: Added a blank line at the end of each file Ignore generator-exercise when linting exercise files Update exercise number of each exercise Update exercise number
33 lines
1.2 KiB
Markdown
33 lines
1.2 KiB
Markdown
# Exercise 13 - Caesar cipher
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Implement the legendary Caesar cipher:
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> In cryptography, a Caesar cipher, also known as Caesar's cipher, the shift cipher, Caesar's code or Caesar shift, is one of the simplest and most widely known encryption techniques. It is a type of substitution cipher in which each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet. For example, with a left shift of 3, D would be replaced by A, E would become B, and so on. The method is named after Julius Caesar, who used it in his private correspondence.
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Hint: You may need to convert letters to their unicode values. Be sure to read the documentation!
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write a function that takes a string to be encoded and a shift factor and then returns the encoded string:
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```javascript
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caesar('A', 1) // simply shifts the letter by 1: returns 'B'
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```
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the cipher should retain capitalization:
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```javascript
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caesar('Hey', 5) // returns 'Mjd;
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```
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should _not_ shift punctuation:
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```javascript
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caesar('Hello, World!', 5) //returns 'Mjqqt, Btwqi!'
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```
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the shift should wrap around the alphabet:
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```javascript
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caesar('Z', 1) // returns 'A'
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```
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negative numbers should work as well:
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```javascript
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caesar('Mjqqt, Btwqi!', -5) // returns 'Hello, World!'
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```
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