How to use the same variable in different functions in GUI MATLAB

I have a popup menu with the following code. There are two options as C1 and C2. If the user selects C1, I want to set the value as 10 and if the user selcts C2, I want to set the value as 20.

    function pop_Callback(hObject, eventdata, handles)

    contents = cellstr(get(hobject,'String'));
    A = contents{get(hObject,'Value')};
    if (strcmp(A,'C1'))
        X = 10;
    elseif (strcmp(A,'C2'))
        X = 20;
    end
    set(handles.pop,X)

I want to use another function with a pushbutton and static text to display the answer, where the output is, Whatever the set value + 12.

    function push_Callback(hObject, eventdata, handles)

    inX = get(handles.pop,X);
    out = inX;
    set(handles.ans,'String',out)

However, I have some error in set and get function.

Answer 1

[Stephen23]

At the end of a callback handles is not stored automatically, or somehow passed to other callbacks/functions. You have to do this explicitly, by calling guidata at the end of the callback:

guidata(hObject,handles)

Only then can you get .pop in the other callback. See the examples in the documentation:

https://www.mathworks.com/help/matlab/ref/guidata.html

https://www.mathworks.com/help/matlab/creating_guis/share-data-among-callbacks.html

href = ""</a>

[Mech Stud]

Thanks for the guidance. I read and edited my code as follows

contents = cellstr(get(hobject,'String'));
A = contents{get(hObject,'Value')}
data = guidata(object_handle);
if (strcmp(A,'C1'))
    data = 10;
elseif (strcmp(A,'C2'))
    data = 20;
end
guidata(object_handle,data)
set(handles.pop,data)

function push_Callback(hObject, eventdata, handles)

in = get(handles.pop,'String');
answ = in;
set(handles.ans,'String',answ)

However, The 'answ' is C1 and C2 (The 'Value' or the pull down menu option).