lamda=1;
SampleTime = 0.01;
c=0;
 count=zeros(2001,1);
 dt=[];
 x = rand(2001,1);
P = cdf('poiss', lamda/SampleTime, 0:SampleTime:20); 

for i =1:length(x)

if x(i) <= P(i) 
dt=[dt SampleTime*i];
c=c+1;  P(1:i)=zeros(i,1);
P(i+1:length(P))=P(1:length(P)-i)  
end
 count(i) =c;
  end 

plot([0:0.01:20]', count)