MATLAB: Error in the code

Question

Hi, everybody, MATLAB tells me that this code in the 3rd "while" has a problem (MAT is a matrix):

ir=1;
while(ir<=length(MAT(1,:)))
ic=1;
while(ic<=length(MAT(:,1)))
while(MAT(ir,ic)==0)
MAT(ir,ic)=6;
 end
ic=ic+1;
end
ir=ir+1;
end

Just to be more precise: with this code I want to replace the zero entries of the matrix MAT with the number 6. Thank you!

Answer 1

Just do

MAT(MAT == 0) = 6;