I need help with defining while loops?

Hello. I want write a code which can performe to generate matrix automaticlly. In the last while loop in my code I want to define that the 3:rd column and 2:nd row is =5 and the 2:nd column and 2:nd row is = 7 and the rest of the row tow is = 0 when we do not have any more number. Plz help me to solve this issue.

My code

% -------------------------------------
a=386;
b=75;
nrows=2;

stra= num2str(a);    %#########convert (a) to string format
strb=num2str(b);     %#########convert (b) to string format

sizea= length(stra);   
sizeb= length(strb);  

% M=zeros(sizea, sizeb);

if sizea > sizeb
    ncols = sizea       
    M= zeros (nrows, ncols)

      while sizea >= 1
          M(1, sizea) =  str2num(stra(1, sizea)) %(stra(stra(1), size(a)))
          sizea=sizea-1
      end
          else

          ncols=sizeb
      M=zeros (nrows, ncols)

end 

while sizeb >= 1
    M(2, sizeb) = str2num(strb(1,sizeb))
    sizeb=sizeb-1
    sizea=sizea-1
end

[Stephen23]

@Najib Ahmadi: most of the volunteers here already know how to write efficient MATLAB code. What we don't know is exactly what you are trying to do. We can fix your code, or write something to help you, but you need to explain exactly what you need.

Please post input and output data that we can test code with, and an detailed explanation. Posting broken code does not help us to understand what you are trying to achieve.

[Thorsten]

What is the expected output in your example with a=386 and b=75?

Answer 1

[Eng. Fredius Magige]

Your increment is missing which support to allow application of while. Both if and else are inner within wile loop as well as to end by end.

[Najib Ahmadi]

Is it possible for you write the code. Because in my case it did not work! appriciate for ur help

Answer 2

[Thorsten]

Do you want to put the digits of a "a" and "b" into the elements of a matrix? The you can use this code:

 M = num2str([a; b]) - '0'; 
 M(M==' ' - '0') = 0
 M =
     3     8     6
     0     7     5