function callcheck(htext,str1,z,vchk1,vchk2)
cla,set(htext,'string',[str1,sprintf('%1.4g\',z)]);	%更新靜態(tài)文本框內(nèi)容	<2>
dt=0.1;t=0:dt:15;N=length(t);y=step(1,[1 2*z 1],t);plot(t,y);
if vchk1 									%假如峰值框被選中						<4>
   [ym,km]=max(y);
   if km<(N-3)							%假如在設(shè)定時(shí)間范圍內(nèi)能插值			<6>
      k1=km-3;k2=km+3;k12=k1:k2;tt=t(k12);
      yy=spline(t(k12),y(k12),tt);						%局部樣條插值			<8>
      [yym,kkm]=max(yy);								%求更精確的峰值位置
      line(tt(kkm),yym,'marker','.',...				%畫峰值點(diǎn)				<10>
         'markeredgecolor','r','markersize',20);
      ystr=['ymax = ',sprintf('%1.4g\',yym)];
      tstr=['tmax = ',sprintf('%1.4g\',tt(kkm))];
      text(tt(kkm),1.05*yym,{ystr;tstr})
   else									%假如在設(shè)定時(shí)間范圍內(nèi)不能插值		<15>
      text(10,0.4*y(end),{'ymax --> 1';'tmax --> inf'})
   end
end
if vchk2									%假如上升時(shí)間框被選中				<19>
   k95=min(find(y>0.95));k952=[(k95-1),k95];
   t95=interp1(y(k952),t(k952),0.95);					%線性插值				<21>
   line(t95,0.95,'marker','o','markeredgecolor','k','markersize',6);
   tstr95=['t95 = ',sprintf('%1.4g\',t95)];
   text(t95,0.65,tstr95)
end