You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: spm_wft.m
    path of file: ./repos/ExploreASL/External/SPMmodified
    
    the code of the file until where you have to start completion: function [C] = spm_wft(s,k,n)
% Windowed fourier wavelet transform (time-frequency analysis)
% FORMAT [C] = spm_wft(s,k,n)
% s      - (t X n) time-series
% k      - Frequencies (cycles per window)
% n      - window length
% C      - (w X t X n) coefficents (complex)
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging

% Karl Friston
% $Id: spm_wft.m 6977 2016-12-24 17:48:44Z karl $

% window function (Hanning)

    
function [C] = spm_wft(s,k,n)
% Windowed fourier wavelet transform (time-frequency analysis)
% FORMAT [C] = spm_wft(s,k,n)
% s      - (t X n) time-series
% k      - Frequencies (cycles per window)
% n      - window length
% C      - (w X t X n) coefficents (complex)
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging

% Karl Friston
% $Id: spm_wft.m 6977 2016-12-24 17:48:44Z karl $

% window function (Hanning)
%--------------------------------------------------------------------------
[T,N] = size(s);
h     = 0.5*(1 - cos(2*pi*(1:n)/(n + 1)));
h     = h'/sum(h);
C     = zeros(length(k),T,N);

% spectral density
%--------------------------------------------------------------------------
for i = 1:length(k)
    W      = exp(-1j*(2*pi*k(i)*(0:(T - 1))/n))';
    for j = 1:N
        w        = conv(full(s(:,j)).*W,h);
        C(i,:,j) = w((1:T) + n/2);
    end