用guide打开时，运行没问题，但是直接运行.fig文件时出错，command窗口出现以下红色文字：
Attempt to reference field of non-structure array.
Error in Approximation>pushbutton2_Callback (line 158)
x0=str2num(get(handles.edit1,'String'));
Error in gui_mainfcn (line 96)
feval(varargin{:});
Error in Approximation (line 42)
gui_mainfcn(gui_State, varargin{:});
Error in
@(hObject,eventdata)Approximation('pushbutton2_Callback',hObject,eventdata,guidata(hObject))
Error while evaluating uicontrol Callback
这到底是什么原因啊？请高手指点啊。！
