Solving the Kinematic Equations using Runge-Kutta

I am attempting to write a physics simulation program using the kinematic equations and using Runge-Kutta to solve them to determine how an object will move through space subject to certain gravitational forces etc.

I have x=vt+(at^2)/2 as the equation i need to solve using Runge-Kutta.

I've attempted to find code online to help, but what i've found has been mostly the spring equations, nothing dealing with pure kinematics.

If someone knows of a place i could get code for this, in any programming language it would be much appreciated!

thanks in advance