In an assignment A(I) = B, the number of elements in B and I must be the same. any help.

clear all
close all
clc

if ~isempty(instrfind)
   fclose(instrfind);
   delete(instrfind);
end
arduino=serial('COM1','BaudRate',9600); %5aly balak mn el baud rate w el COM number % create serial communication object on port COM18
fopen(arduino); % initiate arduino communication
CM(1)=0;
time(1)=0;
i=1;
tic;
while (toc<=20)
  CM(2)=fscanf(arduino,'%f');
  time(2)=toc;
  figure(1);
  grid on;
  axis([toc-10, toc+10, 0, 35])
  h(i)=plot(time,CM,'b','LineWidth',4);
  hold on
  CM(1)=CM(2);
  time(1)=time(2);
  if(i >= 300)
    delete(h(i-299));
  end
  i=i+1;
  % ew3a t7oot pause w 5aly el delay fee el arduino msh aktar mn 50
  % milliseconds
end
fclose(arduino); % end communication with arduino

[dpb]

Well, not even a hint of which line erred???

I've expounded on the issue several questions the last couple days...search for answered_by: dpb and the phrase and should find at least two if not three or more...