MATLAB: How to do this one..?

ascendingdescrndingMATLABsorting

Suppose I have three numbers 6 3 and 9
I want to assign
x1=lowest number
x3=highest number
x2= remaining number 
How to do this??

Put the numbers into a vector, sort the vector, then make assignments to your variables from this sorted vector.

your ‘x’ variable is a scalar, by definition a (1x1) ‘array’. So ‘x(k)’ is only valid for x=1.

This will likely eliminate that error:

str(count)=x;

[~,idx] = min(A);
s = size(A);
A(sub2ind(s,idx,1:s(2))) = B(end,:);