How to use parameters and arguments in java?

Question

I don't understand the connect or the difference between parameters and arguments. Can you use either as a method? How do you return an argument? Any help is greatly appreciated.

Answer 1

Warning: a lot of people don't differentiate between "parameter" and "argument". They should, but they don't - so you may well see a lot of pages with incorrect uses of the terms.

When you declare a method or constructor, the parameters are the bits you put in declarations to receive values to work with. For example:

public void foo(int x, int y)

Here x and y are the parameters. Within the method, they just act like local variables.

When you call a method or constructor, the arguments are the values that you pass in. Those act as the initial values of the parameters. So for example:

foo(5, 3);

Here 5 and 3 are the arguments - so the parameter x will start with a value of 5, and the parameter y will start with a value of 3. Of course, you can use a parameter (or any other variable) as an argument too. For example:

public void foo(int x, int y) {
    System.out.println(y);
}

Here y is a parameter in the foo method, but its value is being used as the argument to the println method.

Can you use either as a method?

No, they're a completely different concept.

How do you return an argument?

Again, that doesn't really make sense. You can use the value of a parameter in a return statement though:

public int foo(int x, int y) {
    // Normally you'd use y for something, of course
    return x;
}