Calculation of two-mass-system with central difference scheme

Dear community,

I would like to ask for help calculating kinetic and potential energy of a two-mass-system shown below.

I have done a standard-analysis and would like to compare it with a central difference scheme solution.

My problem is to translate the formula of the forward central difference scheme into matlab.

Assumptions: F1=F2=0, springs without mass and friction. Velocities are not given.

Thank you very much,

A.C.

[AC]

Edit: m1,m2, k1, k1 are variables