Problem 78. Implement a ROT13 cipher

Created by Cody Team

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Replace each character in string s1 with the character that is shifted 13 positions from it (wrap back to the beginning if necessary). So A ? N, B ? O, and so on until Y ? L and Z ? M. Case of the output should match the case of the input, so a ? n. Non-alphabetic characters are left in place and untouched.

 s1 = 'I love MATLAB'

then

 s2 = 'V ybir ZNGYNO'

See the Wikipedia article for more info.

Solve

Solution Stats

1505 Solutions
667 Solvers

Last Solution submitted on Feb 18, 2020

Last 200 Solutions

Problem Comments

1 Comment

1 Comment

Miles Walker on 15 Nov 2019

Why does the "t" not change in the second word of the second test? The correct answer has an unchanged "t"?

Solution Comments

Solution 1462577

1 Comment

1 Comment

Russell on 14 Mar 2018

Nice problem. Also like the encoder and decoder are the same (ROT13 applied twice gives back the original text).

Solution 1281241

1 Comment

1 Comment

yurenchu on 4 Oct 2017

A small solution that doesn't use "regexp"!

Solution 1278738

1 Comment

1 Comment

yurenchu on 29 Sep 2017

Sorry, mistake in crediting comment in code; this solution is based on Jan's solution (Solution 17079) -- not Jan Orwat's solution.

Solution 1275889

1 Comment

1 Comment

David Verrelli on 25 Sep 2017

A modification of Solution 819585.

Solution 819585

2 Comments

2 Comments

Matthew Landowski on 3 Feb 2016

Not my best work :/

David Verrelli on 25 Sep 2017

It's still interesting to see other logical approaches like this, though.
One thing that can be done is to remove the inner "if" statements, as illustrated in Solution 1275889. https://www.mathworks.com/matlabcentral/cody/problems/78-implement-a-rot13-cipher/solutions/1275889

Solution 141414

2 Comments

2 Comments

Jason Nicholson on 7 Jan 2013

How does this work?

Khaled Hamed on 8 Jan 2013

It is an old trick. You can pass any group of commands wrapped in a regexp command as one string. It used to be fun and can be used virtually for any problem, but I no longer use it since it is against the purpose of Cody.

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Problem 78. Implement a ROT13 cipher

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Problem 78. Implement a ROT13 cipher

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