% Function Name: caesar % Inputs (2): - (char) a string of unknown length % - (d

Question

% Function Name: caesar

% Inputs (2): - (char) a string of unknown length

%              - (double) an integer describing the shift

% Outputs (1): - (char) a coded string using the Caesar cipher

%

% Caeser Cipher Information:

%            The Caesar cipher is named after Julius Caesar, who, according to

%            Suetonius, used it with a shift of three to protect messages of

%            military significance. It is unknown how effective the Caesar cipher

%            was at the time, but it is likely to have been reasonably secure

%   because most of Caesar's enemies would have been illiterate and

%            others would have assumed that the messages were written in an unknown

%   foreign language.

%

%   Caesar ciphers can still be found today in children's toys such as

%   secret decoder rings. A Caesar shift of thirteen is also performed in

%   the ROT13 algorithm, a simple method often used to obscure text such as

%   joke punchlines and spoilers online.

%

%            In the Caesar cipher, each letter is shifted by the specified amount.

%            For example, if the shift is 3, then the letter 'a' would be coded as

%            the letter 'd'.

%

% Function Description:

%            The function takes in a string and then uses the Caesar cipher to

%            encode it. Only letters (both upper case and lower case) should be

%            encoded using the Caesar cipher. Any other characters such as spaces,

%            periods, etc., should not be encoded.

%

% Notes:

%   - The Caesar cipher should work for both positive and negative integers

%     that indicate the shift given by the second input.

%   - There is no limit to the value of the shift number in the second

%     input.

%

% Hints:

%   - The mod() function may be useful.

%

% Test Cases:

%            coded1 = caesar('Thank you Mario!', 4);

%       coded1 => 'Xlero csy Qevms!'

%

%   coded2 = caesar('Iba vby Wypujlzz pz pu huvaoly jhzasl!', -7);

%       coded2 => 'But our Princess is in another castle!'

%

%   coded3 = caesar('Uh, why isn''t this cipher working?', -26);

%       coded3 => 'Uh, why isn''t this cipher working?'

%

%   coded4 = caesar('uggcf://jjj.lbhghor.pbz/jngpu?i=9LsJE438jxt', 65);

%       coded4 => 'https://www.youtube.com/watch?v=9YfWR438wkg'

PLEASE BRIEFLY EXPLAIN SYNTAX

Explanation / Answer

function ascii_out= caesar(encrypted, shift) ascii_out = double(encrypted); for i=1:length(ascii_out) if ascii_out(i) >=65 && ascii_out(i) 90 ascii_out(i) = 64+ ascii_out(i) - 90; end end if ascii_out(i) >=97 && ascii_out(i) 122 ascii_out(i) = 96 + ascii_out(i) - 122; end end end ascii_out = char(ascii_out); % converting back from ascii to letters end; coded1 = caesar('Thank you Mario!', 4); coded1 coded2 = caesar('Iba vby Wypujlzz pz pu huvaoly jhzasl!', -7); coded2 coded3 = caesar('Uh, why isn''t this cipher working?', -26); coded3 coded4 = caesar('uggcf://jjj.lbhghor.pbz/jngpu?i=9LsJE438jxt', 65); coded4

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