problem in Running GUI need help urgent

I am creating a simple GUI to add 2 numbers. But unable to run it as it shows following error. Could anyone tell me what is going wrong.

Error using str2num (line 31)
Requires character vector or array input.

Error in trial>pushbutton1_Callback (line 127) a=str2num(get(handles.edit1,'String'))+str2num(get(handles.edit2,'String'));

Error in gui_mainfcn (line 95) feval(varargin{:});

Error in trial (line 42) gui_mainfcn(gui_State, varargin{:});

Error in matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)trial('pushbutton1_Callback',hObject,eventdata,guidata(hObject)) Error while evaluating UIControl Callback.

Answer 1

[Image Analyst]

Try

num1 = str2double(handles.edit1.String)
num2 = str2double(handles.edit2.String)
a = num1 + num2