As far as the function realization of the software is concerned, it is possible to realize a function from the top to the bottom, that is, after repeated exercises from the bottom to the top and the top to the bottom, each link of the function is well understood. It can only be done after the palm of your hand.
Once a function can be implemented completely top-down, there will be the following advantages:
1. The efficiency will be improved by orders of magnitude.
2. Functional integrity is naturally guaranteed.
3. The robustness of the function will also be naturally guaranteed.
Note that what is said here is the realization of the function, not the design of the function. Due to the characteristics of the design itself, it is easier to do it from top to bottom.