add all the digits in the even position in matlab

Assuming that you have a numeric input (either scalar or matrix/vector) and you want to sum the digits only in the even positions (where the first position is considered even), you may do the following steps:

1. Convert the input into a string using the num2str function.
2. Extract the digits in the even positions using colon indexing and convert them into a numeric vector using the str2num function.
3. Sum the resulting numeric vector using the sum function.

Here's a sample code that implements the above steps:

main.m
function result = sum_even_digits(input)
% This function sums the digits in the even positions of the input.

% Convert the input to a string
s = num2str(input);

% Extract the digits in the even positions
even_digits = str2num(s(2:2:end));

% Sum the even digits
result = sum(even_digits);
end
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You can test the function by calling it with a numeric input:

main.m
>> sum_even_digits(123456789)
ans =
     20
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This means that the sum of the digits in the even positions of the number 123456789 is 20.