How can I save vector values that changes its size each iteration?

I have the following type of code:

 while i<10
    i=i+1;
        while ...
          C=...
        end
    B(i,:)=C;
 end

where C is 1-row vector and B is supposed to be 10-row matrix with each row equal to C from iterations 1:10. The problem is that C changes its size each iteration and I am not sure how to save all its values in form of a matrix.

[Birdman]

Can you share all of your code?

[Miroslav Mitev]

Here is an example:

while i<10
    i=i+1;
          C=1:i;
    B(i,:)=C;
 end

Answer 1

[Stephen23]

N = 10;
B = nan(N,N);
for k = 1:N
    B(k,1:k) = 1:k;
end

Or use a cell array.

[Miroslav Mitev]

Thank you!