How to generate matrix as shown below?

How Can I generate specific matrix, Such as for n = 3, it shoud generate below three matrices.

% for example n = 3
A = [0 0 0 0; 1  0  0  0;2  1  0  0;3  2  1  0 ] ; 
B = [3  0  0  0;2  2  0  0;1  1  1  0;0  0  0  0 ];
C = [0  0  0  0; 0  1  0  0;0  1  2  0;0  1  2  3];

Answer 1

[Jakob]

n = 3;
A(1,1:n+1) = 0;
for i = 2 : n+1
    A(i,1:i-1) = A(i-1, 1:i-1) +1;
end
for i = 1: n+1
    B(i,1:i) = (n+1-i);
end
C(1,n+1) = 0;
for i = 2 : n+1
    C(i,:) = C(i-1,:);
    C(i,i) = C(i,i-1)+1;
end