title: about the Matlab GUI
body: <p>In Matlab GUI, I wanna to have to plot: A*sin(x). A is the amplitude. I created a axes,a push buttton, and two edit texts, one is "Amplitude", then other one the the "A" that user will input.
  In the coding part, I don't know what to do.Here's the codes I did so far.</p>
  
  <pre><code>function pushbutton1_Callback(hObject, eventdata, handles)
  plot(sin(0:.1:10))
  
  function input_ampli_Callback(hObject, eventdata, handles)
  
  function input_ampli_CreateFcn(hObject, eventdata, handles)
  
  input = str2num(get(hObject,'String')); 
  
  if (isempty(input))
      set(hObject,'String','0')
  end
  
  % Hint: edit controls usually have a white background on Windows.
  %       See ISPC and COMPUTER.
  
  if ispc &amp;&amp; isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
      set(hObject,'BackgroundColor','white');
  end 
  </code></pre>