hello guys, im still a newbie when it comes to OOP...

why the function "salestax" has 2 parameters are they really necessary... thank you very much

function salestax($price,$tax) {
$total = $price + ($price * $tax);
echo "Total cost: $total";
}

I'm a n0ob too, but I think they are important. Since it is a function, it can be called from another place, passing different values from it.

Example:

function salestax($price,$tax) {
    $total = $price + ($price * $tax);
    echo "Total cost: $total";
}
; some code here...
salestax(25.00, 0.2) ; Calls the sales tax fuction above.
; more code here...
salestax(27.50, 0.13) ; You can call it again, passing another set of values.
; more code here...

The output would be:

Total cost: 30 ; from the first call.
Total cost: 31.075 ; from the second call.

BTW, I'm not sure, but I think this is not OOP...

Hope this helps.

 thank you modchip .. What if i remove the parameter it will still run right? but what will be the negative effect of it? thank you...

the parameters are there because THEY ARE NEEDED in order to come up with the desired result. if they're not needed, they shouldn't be there.

you have to declare a global variable if you don't want the parameters but thats not a good practice... 

 As boss cruizer and Dwarvend said, the parameters are needed. It is because the function will be expecting this 2 values. If you think about it, *what will the function compute*?