I am unable to get any Cn values(FS coefficients) and also the graph did not appear. Also error said that (the value assigned to variable 'R' might be unused. I quite lost why and how

clc; clear ; close all;
%Define parameters
Xo=1; %amplitude
T=10; % Total range
To=20; %period
n=8;     %8 harmonics
N=1001;  %Number of points to consider
t=linspace(-(-To-T),(To-T),N);  %Time axis
x=zeros(1,N); x(t>=-T/2 & t<=T/2) = Xo;  %original signal
R=0; % initialize approximated signal
k=-n:n;  %Fourier coefficient number axis 
f=zeros(1,2*n+1); %Fourier coefficient values

for c=0:n   
    for nh = -c:c 
        if nh~=0
            Sinc = (sin(pi*nh*T/To)/((pi*nh*T/To)));
        else 
            Sinc = 1;
        end
        
        Cn = (Xo*T/To)*Sinc ;  %actual FS coefficient 
        f(k==nh) = Cn;  %put the FS coefficient at respective places
        R = R + Cn*exp(1j*nh*2*pi/To.*t);
    end
    R = real (R) ; %to get rid of imaginary factor
    
    %plots
    
    %for plotting the magnitude spectra and plot the FS coefficients
    subplot 121; stem (k,f); grid on ; 
    xlabel('Fourier coefficient index') ; ylabel('magnitude');
    title('Fourier coefficients');
    R=0; %reset approxmation to calc a new one
    
    %for plot gibbs phenomenon
    subplot 122; plot(t,x,t,R); grid on;
    xlabel('Time(t)'); ylabel('Amplitude');
    title (['Approximation for n=8', nums2str(c)]);
end

Answer 1

[Cris LaPierre]

The only error I get with your code is in the last line: nums2str

Once I replaced it with num2str, it ran without error and generated a couple plots. I can't tell you if the values generated are correct or not, though.