How can assign value to a field of structure?

I have a structure A of size (A,1)=10. I want to assign value 1 to one of the fields of A from 1 to 5. The output will be:

A(1).B=1

A(2).B=1

A(3).B=1

A(4).B=1

A(5).B=1

B is one of the fields of A.

I can do it by using loop. Is it possible to avoid loop?

Answer 1

[Matt J]

[A(1:5).B]=deal(1)