b=50

You should know the following knowledge points:

Pass parameters by value

When passing parameters by value, only one copy of the variable is passed. If the process changes the value, the change will only affect the copy, not the variable itself. Use the ByVal keyword to indicate that the parameter is passed by value.

Pass parameters by address

Pass parameters by address to make the procedure use the memory address of the variable to access the contents of the actual variable. Therefore, when a variable is passed to a procedure, the value of the variable can be permanently changed throughout the procedure. Passing parameters by address is the default setting in Visual Basic.

Understand the above knowledge points and you will know.

The difference between integer x and integer byval y