MATLAB: Errors in Menu program

Question

Hi all,

I'm a newbie to Matlab and wrote a program using menu as follows:

*eapplication.m*

choice = eoption;

while choice ~= 4

    switch choice
        case 1
            explaine;
        case 2
            limite;
        case 3
            x = input('Please enter a value for x: ');
            expfn(x);
    end
    choice = eoption;

end

*eoption.m*

choice = menu('Choose an e option', 'Explanation', 'Limit', … 'Exponential function', 'Exit Program');

while choice == 0

disp('Error – please choose one option.')

choice = menu('Choose an e option', 'Explanation', 'Limit', … 'Exponential function', 'Exit Program'); end

*It gave me an error: ??? Attempt to execute SCRIPT eoption as a function: C:\Documents and Settings\Olive\My Documents\MATLAB\eoption.m

Error in ==> eapplication at 1 choice = eoption;*

Could you please shed some lights?

Thanks heaps.

Oliver.

Answer 1

Pretty much what it says. The line choice = eoption; implies that eoption is a function call (because it is asking for an output, to be assigned to choice). But eoption is a script, not a function.

The difference is in how variables are managed. Scripts work with the base MATLAB workspace. Functions use local workspaces, so variables are local. So your options are:

1. Turn eoption into a function by adding the line function choice = eoption at the beginning.
2. Leave eoption as a script and inherit choice from the base workspace. Hence, change the line choice = eoption; (in eapplication) to just eoption;