The port number can be changed, for example, you can set different ports according to your own needs, 30000 or 35000. But if you don't define your own port number, and the system requires a port number, then the default port number will be used. In C language, the definition of default port number is usually put in the header file or directly defined in the program. It is defined as follows:

# Define default port 40000

In short, I hope I can help you.