Change the values of a matrix using indices of another matrix

I have two matrices A and B. I want to know how do I change the values of A with using indexes of B.

A =
     1     2     0     6     3
B =

     1     1     0     1     0

Essentially I want to add 5 to an index of A where B==1 and keep the rest of A unchanged so I can have A be like this. I'd also prefer if someone could show me how I would do this with a while loop.

A =
   6     7     0     11     3

Answer 1

[Mohammad Abouali]

mask = (B==1)
A(mask) = A(mask) + 5

if B is only zero and one then

A(logical(B)) = A(logical(B)) + 5;

and if B is already a logical variable then

A(B) = A(B) + 5;

[Anthony Siddique]

How would I do this if it wasn't just 1's and 0's. If there were multiple conditions with other matrices?

[Walter Roberson]

mask = (C == 7);
A(mask) = A(mask) + whatever_value;