Using function arguments

[uzibalqa]

I am having difficulties understanding how to use gawk function arguments.
Customarily, arguments define variables that are local to the function.

But can arguments be used as input that the function can use

As example

function densel(class,   loc) {
 if (class == 1) { print "Class is 1" }
 if (class == 2) { print "Class is 2" }
 loc = 8
 }

BEGIN {
  class=2
  densel(class)
}

Then there is option of using "return class" which can actually return a value 
by calling

x=densel(class)