Need to utilise only letter ASCII in Caesar Cipher Code

Hello,

I am currently creating a Caesar cipher code and need help, please:

1. A caesar code reverses letter order and capitalisation.

I have written a short code below, which performs the shift correctly, however, I am unsure how to reverse capitalisation, and only edit the letters.

function [out_str] = str_edit(in_str, shift)
char_set = char(32):char(126);
[out_str] = char(in_str+shift);
end

Answer 1

[Walter Roberson]

Hint:

T('A':'Z') = circshift('a':'z', count)
encoded = T(msg)

[Bozza]

Thanks for helping. I'm quite unfamiliar with Matlab, so I am unsure how to implement this into my code?

[Walter Roberson]

Example:

T = char(1):char(255);
T('A':'C') = 'bca';
T('a':'c') = 'BCA';
msg = 'Call a cab!'

msg = 'Call a cab!'

T(msg)

ans = 'aBll B ABC!'

What was uppercase A to C become lower-case and also shifted by 1. What was lowercase a to c become upper-case and also shifted by 1. Things outside of A B C a b c are not affected.

If you calculate the replacement vector based upon your shift count, then the indexing of T with the msg does all of the case changing and shifting at the same time, without any need of a for loop.