MATLAB: How does this matlab function works

Question

Could someone please explain how this function works in defining the matrices

For example,

B=zeros(size(A,1),1); C=eye(size(A));

Answer 1

doc size
doc zeros
doc eye

You can also try an example

>> A=[1 2 3;4 5 6]
B=zeros(size(A,1),1)
C=eye(size(A))

A =

     1     2     3
     4     5     6

B =

     0
     0

C =

     1     0     0
     0     1     0