matlab uicontrol中popupmenu（弹出式菜单）用法,用于显示不同的函数

h0=figure('toolbar','none',...
    'position',[200 150 450 250],...
    'name','实例36');
x=0:0.5:2*pi;
y=sin(x);
h=plot(x,y);
grid on
jb=uicontrol(gcf,'style','popupmenu',...
    'string',...
  <strong>  'sin(x)|cos(x)|sin(x)+cos(x)|exp(-sin(x))',...</strong>
    'position',[250 20 50 20]);
set(jb,'value',1)
huidiao=[... 
    'v=get(jb,''value'');,',...
        'switch v,',...
        'case 1,',...
        'delete(h),',...
        'y=sin(x);,',...
        'h=plot(x,y);,',...
        'grid on,',...
        'case 2,',...
        'delete(h),',...
        'y=cos(x);,',...
        'h=plot(x,y);,',...
         'grid on,',...
        'case 3,',...
        'delete(h),',...
        'y=sin(x)+cos(x);,',...
        'h=plot(x,y);,',...
         'grid on,',...
        'case 4,',...
        'delete(h),',...
        'y=exp(-sin(x));,',...
        'h=plot(x,y);,',...
         'grid on,',...
        'end'];
set(jb,'callback',huidiao)
set(gca,'position',[0.2 0.2 0.6 0.6])
title('弹出式菜单的使用')