Help please,need FreeFem++ code

r is a random number uniformly distributed on [-0.005; 0.005].
what i write the code of r in FreeFem++.
Suppose u=r
Then, what will be w=u^3-u-((\nabla^2 )u);
=u^3-u-\Delta u

Please help.
I need FreeFem++ code of u=r and w.