Matlab - Problema en GUI

if A ~=0 &&  B ~=0  && C ~=0

que en el static text aparezca A+B+C

end

function varargout = button_group_caballero1(varargin)

gui_Singleton = 1;

gui_State = struct('gui_Name',       mfilename, ...

                   'gui_Singleton',  gui_Singleton, ...

                   'gui_OpeningFcn', @button_group_caballero1_OpeningFcn, ...

                   'gui_OutputFcn',  @button_group_caballero1_OutputFcn, ...

                   'gui_LayoutFcn',  [] , ...

                   'gui_Callback',   []);

if nargin && ischar(varargin{1})

    gui_State.gui_Callback = str2func(varargin{1});

end

if nargout

    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});

else

    gui_mainfcn(gui_State, varargin{:});

end

function button_group_caballero1_OpeningFcn(hObject, eventdata, handles, varargin)

handles.output = hObject;

guidata(hObject, handles);

function varargout = button_group_caballero1_OutputFcn(hObject, eventdata, handles)

varargout{1} = handles.output;

function edit1_Callback(hObject, eventdata, handles)

A=str2double(get(hObject,'String'));

handles.A=A;

guidata(hObject, handles);

function edit2_Callback(hObject, eventdata, handles)

B=str2double(get(hObject,'String'));

handles.B=B;

guidata(hObject, handles);

function uipanel1_SelectionChangeFcn(hObject, eventdata, handles)

global C

if hObject==handles.uno

C=2;

elseif hObject==handles.dos

C=10;

elseif hObject==handles.tres

C=15;

end

function pushbutton1_Callback(hObject, eventdata, handles)

global C

A=handles.A;

B=handles.B;

if A~=0 &&  B~=0  && C~=0

    suma=A+B+C;

   set(handles.text3,'String',suma);

else

    set(handles.text3,'String',' ');

end

guidata(hObject, handles);