ode45 is causing an infinite loop

Can someone tell me why my ode45 keeps looping and calling the function without stopping?

 function dcdt = project101r1d1x1(t, c)
dcdt = zeros(size(c));
D = 1.97e10; 
r_cup = 0.075; %r_cup1
h = r_cup / 10;
dcdt(1) = 0;
c11 = (( 2 * r_cup + h^2 ) * c(10) - r_cup * c(9) ) / (r_cup + h) ;
for x = 2 : 9
    dcdt(x) = D * ( ( c(x + 1) - 2 * c(x) + c(x - 1) ) / h^2 + (1 / r_cup) * ( c(x + 1) - c(x - 1) ) / (2 * h));
end
dcdt(10) = D * ( ( c11 - 2 * c(10) + c(9) ) / h^2 + 1 / r_cup * ( c11 - c(9) ) / (2 * h));

 c0 = zeros(10, 1);
x_teabag = 0.04; 
y_teabag = 0.0075;  
z_teabag = 0.06;
c0(1) = (5.03 / 290.26 ) / (2 * x_teabag * y_teabag + 2 * y_teabag * z_teabag + 2 * x_teabag * z_teabag);
tspan = [0 0.1];
r_cup1 = 0:0.0075:.07425;
[t,c] = ode45('project101r1d1x1', tspan, c0);
plot(r_cup1, c(2,:));
legend('t = 0.1 s');
xlabel('r (m)');
ylabel('C (mol/m^3)');