Let's look at an old example:
You can see that the two functions
are both doing the same thing. They
are both putting on screen something.
They are different only because of the value
they put on the screen. Instead of
repeating ourselves, let's create a single
function that can understand what
value we want on the screen.
Take a look:
In this function, we put to the screen
a value that we get from a variable. This
variable gets a new value each time
we execute this function.