function S = sumCubes(v)

% takes a vector as input and returns the sum
% of the cubes of its elements.

% Method 1: a straightforward method
S = 0; 
for i = 1:length(v)
    S = S + v(i)^3; 
end

% Method 2: valid, but not recommended
%S = 0;
%for x = v
%    S = S + x^3;
%end

% Method 3: a natural way to write it in Matlab
%S = sum(v.^3); 

end