clear all
close all


 figure(1)
 subplot(1,2,1)
 title('Plano s')
 hold on
 plot(zeros(1,801),[-40:0.1:40],'b')
 plot([-40:0.1:1],zeros(1,411),'b')

 sgrid

for k=1:10000
set(0,'Current',1)


   
    
 [re,im]= ginput(1); 
 
 s1 = re + i*im;
 s2 = re - i*im;
 plot(re,im,'xr',re,-im,'xr')
 title('Plano s')
 if k>1
 plot(re_ant1,im_ant1,'xb',re_ant1,-im_ant1,'xb')
 end
 re_ant1 = re;
 im_ant1 =im;
 
 
 n=[1];
 d=conv([1 -s1],[1 -s2]);

 Gs = tf(n,d);
 
 Gz =c2d(Gs,.1);
 p = pole(Gz);
 re = real(p(1));
 im = imag(p(1));
 

 
  figure(1)
subplot(1,2,2)
x=-1:0.01:1;
y = sqrt(1 -x.^2);
plot(x,y,'b',x,-y,'b')
hold on
plot(zeros(1,241),[-1.2:0.01:1.2],'b')
plot([-1.2:0.01:1.2],zeros(1,241),'b')
axis([-1.2 1.2 -1.2 1.2])

 plot(re,im,'xr',re,-im,'xr')
 if k>1
  plot(re_ant2,im_ant2,'xb',re_ant2,-im_ant2,'xb')
 end
 re_ant2 = re;
 im_ant2 =im;
 
zgrid 
 
 
    
end