Summing the even index elements of a 1D array

I am trying to write a recursive function that sums the elements in even indexed position of a 1D array, but am not sure how to do this. I have some of the code started below, but it is obvously incorrect:

function [out] = mySumEven(A)

n = length(A);

if n == 1

out = 'No numbers in even positions';

elseif n == 2

out = A(2);

else

out = A(2) + mySumEven(A(4:n));

end

end

Answer 1

[Atsushi Ueno]

mySumEven([1 2 3 4 5 6 7 8 9])

No numbers in even positions

ans = 20

function [out] = mySumEven(A)
n = length(A);
if n == 1
    disp('No numbers in even positions'); % out = 'No numbers in even positions';
    out = 0; % added
elseif n == 2
    out = A(2);
else
    out = A(2) + mySumEven(A(3:n)); % out = A(2) + mySumEven(A(4:n));
end
end

[Atsushi Ueno]

MATLAB can add numerical values and character vectors. The output is as numeric vector. It means every charactor code have been added by 1.

1 + [1 2 3 4]

ans = 1×4

2 3 4 5

1 + 'No numbers in even positions'

ans = 1×28

79 112 33 111 118 110 99 102 115 116 33 106 111 33 102 119 102 111 33 113 112 116 106 117 106 112 111 116

char(ans)

ans = 'Op!ovncfst!jo!fwfo!qptjujpot'

[Camden Nelson]

That makes a lot of sense. Explains why I was getting some bizarre answers. Thank you so much!