my_fft(x)

function x = my_fft(x)
N=length(x);
A=nextpow2(x) ;                %no of levels
x=[x,zeros(1,(2^A)-N)];        %appending zeros
x = bitrevorder(x);
N = length(x);
level = A;
phase = cos(2*pi/N*[0:(N/2-1)])-j*sin(2*pi/N*[0:(N/2-1)]);
for a = 1:level
    L = 2^a;      
    phase_level = phase(1:N/L:(N/2));
    for k = 0:L:N-L   
        for n = 0:L/2-1
            first  = x(n+k+1);
            second = x(n + k + L/2 +1)*phase_level(n+1);
            x(n+k+1)       = first + second;
            x(n+k + L/2+1) = first - second;
        end
    end
end