Ciphers/Encryption trouble with 8bit binary xor encryption

Im having trouble developing a this encryption. Im required to develope a cypher. Thats turns a message into its ascII then into its binary value (8 bit) then combine it with a randomly generated number using xor. I am given some code that will convert the message and save it in a text file.

I thought my code would work but it doesnt and im unsure where im going wrong

The error message im getting is

Attempt to execute SCRIPT encoder as a function:

C:\Users\mick\Documents\MATLAB\prac two\encoder.m

Also have a graph popping up and i have no clue why

the code ive devloped so far:

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text = input('Enter what you want to code ', 's')

function [c_text, key] = encode(text)

N = length(text);
text = uint8(text);

key = randi([20 200], 1);
b_key = de2bi(key, 8, 'left-msb');

c_text = ''; %initialize an array for the coded message

    for k = 1:N
        b_c_text = xor(de2bi(text(k), 8, 'left-msb'), b_key);
        d_c_text = bi2de(b_c_text, 'left-msb');
        c_text(k) = d_c_text;
    end
end
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The given code

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clear, clc


% Call my encoder function
[codedmessage, key] = encode(plaintext);
%Output coded message
fprintf('%c', codedmessage)
fprintf('\n')

%write encoded message to a text file
fid = fopen('group_text.txt', 'w'); %Open the file for write access 'w'
fwrite(fid, codedmessage); %Write message to open file
fclose(fid); % important, must release file back to Operating System after we're done

clear codedmessage

%Read encoded message from a text file
fid = fopen('group_text.txt', 'r'); %Open the file for read access'r'
codedmessage = fread(fid); % Read the data out of the file
fclose(fid); %important, must release file back to Oprating System after we're done

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any help would be appricated

Answer 1

[Walter Roberson]

Remove the line

text = input('Enter what you want to code ', 's')

from encode.m

In your other file, before the line

% Call my encoder function

insert the line

plaintext = input('Enter what you want to code ', 's');

[MIchael Brennan]

Thanks Walter I didnt realise i had a varible also incorrectly labeled . Much appreciated