OCP (Open-Close principle)

Open-closed principle Software
"Open-Close principle" in Design"

This principle was first proposed by Bertrand Meyer.
Entities shocould be open for extension, but closed
Modification. It means that a software entity should be open to extensions and closed to modifications. That is to say, when designing a module, we should enable this module before it is not modified.
Extension. In other words, you do not need to modify the source code.
To change the behavior of this module.

Satisfying the OCP design brings two unparalleled advantages to the system.

1. By extending existing software systems, new behaviors can be provided to meet new demands for software and make the changed software systems adaptive and flexible.

2. The existing software modules, especially the most important abstract layer modules, cannot be modified any more, which makes the software system in change stable and continuous.

For example:
The factory method in programming mode supports the OCP Principle