CNC Machining several principles?

In the machining of CNC lathes, the determination of the processing route generally follows the following principles.
1 should ensure the accuracy and surface roughness of the workpiece being machined.
2 The processing route is the shortest, the idle travel time is reduced, and the processing efficiency is improved.
3 Simplify the workload of numerical calculations and simplify the processing procedure.
4 For some reusable programs, subroutines should be used