creating GUI using existing code

I just finished a long and complicated program on matlab and should make a GUI for it everything I´ve found is telling me to re-write the code in the guide command or to call a function in the guide. but re-writing the code is impossible and the program doesn't have functions to call, it´s a series of loops and if-s.

[Stephen23]

" but re-writing the code is impossible and the program doesn't have functions to call"

If you want to write reliable code that can be integrated into a GUI then use functions. Scripts are basically useless for anything more complex than just testing out a new idea, and should be totally avoided for anything that is "long and complicated". You need to write functions.

https://www.mathworks.com/matlabcentral/answers/228557-experts-of-matlab-how-did-you-learn-any-advice-for-beginner-intermediate-users

[Dennis]

i agree with Stephen and with the informations you have given it is hard to provide a better answer. Depending on what your program does and what the gui is supposed to do you could just wrap your code in a function and create a gui that executes it

GUI:

function glac()
%GUI for long and comlicated code
fig=figure;
pushbutton1=uicontrol('Style','pushbutton','String','Execute','callback',@lacf);
end

function lacf(~,~)
%long and complicated code function
    disp('Hello Matlab!')  %replace this with long and complicated code ?
end