concatenate 2 matrix in loop "previous iteration"?

i am trying to concatenateconcatenate two matrix

the output i get same line not append previous iterations C with new C

5.0000 3.6000 1.4000 0.2000

5.0000 3.6000 1.4000 0.2000

while(i ~=4)
    
    Datachunk(i) = next_line;
    
      i = i + 1;
    next_line = fgetl(fid);
    C = cell2mat(textscan(next_line,'%f %f %f %f','Delimiter', ',','CollectOutput', true));
    C4 = [C;C];
    
end

Answer 1

[KALYAN ACHARJYA]

May be you replaced the privious C with current C, use copy privious C with other variable and do the same.

while(i ~=4)
    Datachunk(i) = next_line;
      i = i + 1;
    next_line = fgetl(fid);
    D=C; %privious C, do C initialization (before while loop) for 1st iteration.
    C=cell2mat(textscan(next_line,'%f %f %f %f','Delimiter', ',','CollectOutput', true));
    C=[D;C];
    
end

Hope I undestand the question, if not let me know, I will happly delete the answer.

[E]

really that what happened it be replaced

i did this but not working

V=C;

C4 = [C;V]

[KALYAN ACHARJYA]

Have you initialize C (before while loop) for 1st iteration? Try the following one-

C=zeros(1,4);
while(i ~=4)
    Datachunk(i)=next_line;
    i=i+1;
    next_line = fgetl(fid);
    D=C; %privious C, do C initialization (before while loop) for 1st iteration.
    C=cell2mat(textscan(next_line,'%f %f %f %f','Delimiter', ',','CollectOutput', true));
    C=[D;C]; 
end

Let me know is it working?

[E]

now it is working

while(i ~=4)
    
    Datachunk(i) = next_line;
    
      i = i + 1;
    next_line = fgetl(fid);
    
    C = cell2mat(textscan(next_line,'%f %f %f %f','Delimiter', ',','CollectOutput', true));
    
    C4 = [C4;C];
    
end

[KALYAN ACHARJYA]

OK

C=[D;C];

[E]

thanks so much