This lesson is called songwriting with parameters.

We're going to be writing some songs here.

Sometimes the chorus is just a little bit
different each time you sing it.

Do you remember Old Macdonald Had a Farm?

The chorus is slightly different for each
animal.

And on that farm, he had a cow, e-i-e-i-o.

The small change in each chorus can be shown
using something we call parameters.

Sometimes a function needs a parameter.

A parameter is an extra piece of information
you can pass to a function to customize it

for a special need.

When you make ice cream sundaes with your
friends, you are using a process similar to

parameters in a computer program.

The disk of vanilla ice cream might be the
same for every sundae but when you ask your

friends which two toppings they'd like, you
could get lots of different combinations.

Topping is the function name but each type
of topping is a parameter.

Functions and parameters work together to
make great computer programs and great sundaes

too.