There are two ways of passing arguments to a function, by value or by reference.

To pass by value, you simply name the variables in the function definition:
Code:
void functionByValue(int a, float b)
{
   // yada yada yada
}
What this does is make a copy of the variables passed to the function and uses them locally, hence, by value.

The other way to pass variables is by reference, which looks like this:
Code:
void functionByValue(int a&, float b&)
{
   // yada yada yada
}
What this does is pass a reference (pointer) to the "calling" variable, rather than copy it's value. This means that if you change the value of a to 2 in the function, the original a will be changed to 2. This is useful when you want to return more than one value from a function.

You can also mix and match by reference and by value:
Code:
void functionByValue(int a&, float b)
{
   // yada yada yada
}
In this case a local copy of b will be made and a will point to the "calling" a.

Hope this helps.

<b>EDIT:</b> Also, I don't know what book(s) you are using in class, but I used <a href="http://www.amazon.com/gp/product/0672323087/qid=1143132976/sr=2-1/ref=pd_bbs_b_2_1/104-9506222-3431117?s=books&v=glance&n=283155">Object-Oriented Programming in C++ by Robert Lafore</a> and it makes learning C++ a lot easier. Granted, I have the 2nd edition (was the current one when I was in school) and the current one is the 4th edition. But regardless, it's a great book and I highly reccomend it.