Where am I going wrong in setting up this function?

For starters, I hae no clue how to use matLAb, I could program this easily in python or C++ but here I'm at a loss for how function definitions occur: The code below is a function I'm trying to get to work, but clearly it wants to throw errors about not enough input arguments. So what am I missing here, how would I pass x in as an array of length N and why is N raising errors of its own?

function X = dft(x, N)
X = [];
w = 2*pi/N;
    for l = 1:N
        X(l) = symsum( x(k)* e^(-(1i)*l*k*w), k, 0, N-1 );
    end
end

Answer 1

[VBBV]

 X(l) = symsum( x(k)* exp(-(1i)*l*k*w), k, 0, N-1 );

use exp function

[Justin Arackel]

oy vey, thx a lot