function pos = findGGT(dna)

% Vector pos stores the locations where string 'GGT' occurs in char vector dna.



pos= [];  % vector of locations where 'GGT' occurs

for k= 1: length(dna)-2

    % Check for 'GGT' in dna(k:k+2)

    % Last location to check for a length 3 substring is length-2

    if (dna(k)=='G' && dna(k+1)=='G' && dna(k+2)=='T')

        pos= [pos k];

    end

end