Need suggestion on Code conversion to Matlab_extension 1

Question

This is an extension of the previously asked question: link. In a short, I am trying to convert a C program into Matlab and looking for your suggestion to improve the code as th

Answer 1

EDIT:

Try this it do the same think as the c function: The lengh of S should be >= 256 or you will exceed it as mod() could return such index. I suggest you to change 256 in the function with the lenght provided to solve this issue.

Here you don't need the key variable.

function out = prga(S, len)
    i=0; j=0; x=[]; t=[];
    for x=0:len-1
        i = mod(i+1, 256);
        j = mod(j+S(i+1), 256);
        t = S(i+1);
        S(i+1) = S(j+1);
        S(j+1) = t;
    out(x+1) = S(mod(S(i+1)+S(j+1), 256)+1);
    end
end

Or you can use the key variable to controle the loop

function out = prga(S, key)
    i=0; j=0; x=[]; t=[];
    for x=0:length(key)-1
        i = mod(i+1, 256);
        j = mod(j+S(i+1), 256);
        t = S(i+1);
        S(i+1) = S(j+1);
        S(j+1) = t;
    out(x+1) = S(mod(S(i+1)+S(j+1), 256)+1);
    end
end