Matlab code to solve 1D diffusional equation

The requirement is to solve the given one dimensional transient diffusion equation method, by Crank Nicolson method. Diffusion equation: ∂C/∂t= (D (∂^2 C)/(∂x^2 ) )+ q Initial condition: C(x,0)= 0 Boundary condition: C(0,t)= 0.2235 * exp(-0.025*t), when x=0 ∂C/∂t = 0, when x= L

time step:180s, h=0.05