How to debug the 'matrix dimension not agree' when solving matrix time by time using loop (with code)

I want to create a function with for-loop to keep solving a matrix by assigning the previous solution to the next matrix equation, I could only run for one time of the loop, then it showing that my matrix dimension is not agree at the 2nd loop.

Code:

 function X = MatrixSolu()
 X=5*ones(4,1);
 A = [5 2 6 4; 9 8 6 5; 5 8 4 2; 9 5 4 6];

 for i=1:12
    b=X;
    X=b\A;
    fprintf('%14.2',X);
 end

Answer 1

[Geoff Hayes]

Sichen - if you step through your code, you will note that X is initially a 4x1 but after solving for X as

 X = b\A;

it becomes a 1x4 array. I think that to solve this system of linear equations (as per the examples found here mldivide), you want to do something like

 X=5*ones(4,1);
 A = [5 2 6 4; 9 8 6 5; 5 8 4 2; 9 5 4 6];
 for i=1:12
    b=X;
    X=A\b;
    fprintf('%14.2f',X');
    fprintf('\n');
 end

as x = A\b solves the system of linear equations A*x = b. Though it isn't clear to me why you want to solve your equations in this manner.