Where is the problem with my code. it never ends !!

What is the problem with the following code?

It calculates the exponential coefficients fo fourier series of periodic function f(t).

when I run it the compilation never ends !! and I must close matlab and run it again.

function [an]=fc(f,T)
syms t n
n=-20:1:20;
an=(1/T)*int(f*exp(-1i*n*2*pi*t/T),t,0,T);
end

syms t  n
 f=rectangularPulse(t/4)*(abs(t)-1);
%f=rectangularPulse(t);
% f=sin(t);
 Y=fc(f,20);

subplot(211)
stem(-20:1:20,abs(Y));
ylabel('|an|')
grid;

subplot(212)
stem(-20:1:20,angle(Y));
ylabel('<an')
grid;

Answer 1

[Geoff Hayes]

geometry - your function appears to be recursive

function [an]=fc(f,T)
syms t n
n=-20:1:20;
an=(1/T)*int(f*exp(-1i*n*2*pi*t/T),t,0,T);
end
syms t  n
f=rectangularPulse(t/4)*(abs(t)-1);
%f=rectangularPulse(t);
% f=sin(t);
Y=fc(f,20);    % <------------------

So it continually calls itself and without a stopping condition, it will call itself forever (!).