How can I combine these two codes?

I am studying the book "Contemporary Communication Systems using MATLAB", and I am stuck on question 1.4. I should use the m-file fseries.m:

function xx=fseries(funfcn,a,b,n,tol,p1,p2,p3)
args0=[];
for nn=1:nargin-5
  args0=[args0,',p',int2str(nn)];
end
args=[args0,')'];
t=b-a;
xx(1)=eval(['1/(',num2str(t),').*quad(funfcn,a,b,tol,[]',args]) ;

for i=1:n
  new_fun = 'exp_fnct' ;
  args=[',', num2str(i), ',', num2str(t), args0, ')' ] ;
  xx(i+1)=eval(['1/(',num2str(t),').*quad(new_fun,a,b,tol,[],funfcn',args]);
end

but after debugging this error appears:

Error in ==> fseries at 19
t=b-a;

as I understood the [a,b] is an interval and the signal in the interval [a,b] is given in an another m.file:

n=[-20:1:20];
x=abs(sinc(n/2));
stem(n,x);

so, how can I combine these two and solve the question?

Thanx

Answer 1

[Jan]

Not an answer!

At first omit the strange EVAL junk:

function xx=fseries(funfcn,a,b,n,tol,varargin)
t=b-a;
xx(1) = 1/t .* quad(funfcn,a,b,tol,[],varargin{:});

for i=1:n
  xx(i+1) = 1/t .* quad(@exp_fnct, a, b, tol, [], funfcn, i, t, varargin{:});
end

This looks easier, doesn't it?