How can I improve this decoder

I have to do a decoder for this code, I made one, but the final string (string3) come out with the letters in the order that the encode code gives. What can i do to have the original order of the string? thanks for the help.

%% This is the encode code

function [string1,code]=codificar(string)

b=double(string);

if b(end)<b(1)

[a,c]=sort(b,'descend');

else

[a,c]=sort(b);

end

string1=char(a+1);

code=c;

end

%% And this is what a made

function [string3]=decodificar(string2) % I put string2 and 3 to no confuse with the original string

a=double(string2);

if a(1)<=a(end)

[b,g]=sort(a);

else

[b,g]=sort(a,'descend');

end

string3=char(b-1);

code=g

end

[Walter Roberson]

You cannot return to the original order without knowing the code variable. Consider that bard and brad would have the same output string1, so string1 by itself is not enough information to recover the original string.

[Sebastian Molina Sazo]

I have to put the original function in the decoder?