For inverse kinematics code you need to know the position/path on which the End effecter needs to move. Once you have the path coordinates(x,y,z) you can use those to get the angles required by using the DH method (incudes using Robotic-arm length and angular moments), as you get angles, verify them using forward kinematics and send those angles to the actuator using )ex: Arduino) in a custom-sweep manner using mapping command for smooth arm moment.

Since it sounds like you are planning on running this solution on hardware Start by checking your forward kinematics “zero” configuration as a sanity check.

Then check the forward kinematics of each joint one at a time with simple +\-90 degrees. That’s all easy, but infinitely useful to prevent crashing in real life.

Then the easiest numerical method is to use the manipulator Jacobian to iteratively find the inverse kinematics which only works if your processor has extra clock cycles between each step of an interpolated move.

The most straight forward closed form solution which will always be faster than the manipulator Jacobian method is to use the Padem Kahn sub problems to start at the end effector and solve each joint angle. If you are using a commercial robot it will either have a spherical wrist or have less than 6 DOF and will therefore have a closed form solution.

https://en.m.wikipedia.org/wiki/Paden%E2%80%93Kahan_subproblems

This guy made a 6 DOF robot that work with IK/FK on arduino.
https://www.youtube.com/watch?v=Sgsn2CM3bjY

The code on github :
https://github.com/SkyentificGit/SmallRobotArm

I hope it help :)

Can you give us more information ?

https://www.codegrepper.com/code-examples/whatever/write+a+program+for+forward+kinematics+and+inverse+kinematics+of+robot