What is the difference between parameters and arguments in VB?

Answer 1

In programming languages, a parameter and an argument are the same thing; there is no actual difference between the two. Although a few languages do differentiate between an actual argument and a formal argument by calling one a parameter and the other an argument (or vice versa), the terms are universally interchangeable. That is; there is no single definition that applies to any one language, including Visual Basic.

The language may have a convention, but there's no reason to follow that convention. Personally, I prefer the term argument and use the terms formal argument and actual argument whenever I need to specifically differentiate one from the other. In this way I can refer to them in a consistent but language-agnostic manner. Only a Pedant would argue that the terms parameter and argument have a specific meaning to a specific language, even when the creators of that language use the terms interchangeably themselves.

To clarify, an actual argument is the argument being passed to a function while a formal argument is the argument that is used by the function. The two will always have the same value, but they are not the same argument.

For instance, consider the following function definition:

f (int a) { print a*2 }

Whether we regard 'a' as being a parameter or an argument is immaterial -- it is a formal argument or formal parameter, whichever you prefer. The meaning is clarified by using the word "formal".

Now consider the calling code:

b = 42

f (b)

Here, b is the actual argument (or actual parameter) being passed to the function f. Note that a and b are not the same variable or reference. That alone means there is no reason to differentiate them; the meaning of argument or parameter is implied by the context alone.

It doesn't matter whether the function uses pass by value or pass by reference semantics. When passing arguments by value, a is simply a copy of b (independent variables with the same value). When passing by reference, a refers to the same memory address as b (a is an alias for b). In either case, the function uses the formal argument named a while the calling code uses the actual argument named b. In other words, the names are only accessible from within the scope in which they are declared, even if they refer to the same memory address.

Of course, a function may pass one of its formal arguments to another function. Thus with respect to the calling function, its formal argument becomes an actual argument to the function being called.