How to code with for loop loops without using ndgrid?

Hello, how do I write the following code without ndgrid, that is, with for loop loops, without using a ready-made library.

[A B C]=ndgrid(1:2,3:4,5:6);

A1=reshape(A,[],1);

B1=reshape(B,[],1);

C1=reshape(C,[],1);

d=[A1,B1,C1]

Answer 1

[David Hill]

count=0;
for c=5:6
    for b=3:4
        for a=1:2
            count=count+1;
            d(count,:)=[a,b,c];
        end
    end
end

Answer 2

[Stephen23]

As this is clearly homework, this should get you started:

inp = {1:2, 3:4, 5:6};
[A,B,C] = ndgrid(inp{:});
A1=reshape(A,[],1);
B1=reshape(B,[],1);
C1=reshape(C,[],1);
d=[A1,B1,C1]

d = 8×3

1 3 5 2 3 5 1 4 5 2 4 5 1 3 6 2 3 6 1 4 6 2 4 6

S = cellfun(@numel,inp);
reshape(repmat(reshape(inp{1},S(1),1,1),1,S(2),S(3)),[],1)

ans = 8×1

1 2 1 2 1 2 1 2