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Let's talk now about default parameter
values.

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you saw me go ahead then and add
comma 66 to each line, to fix it.

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So what that means is, we can give our
screen_width parameter a default value.

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So I can come up here, on line one,
in the definition, put equals 80.

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80 is a sensible default, because that's
the default width of many terminals.

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It's usual not to put a
space either side of the equals, when

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providing default values. So if we call
our function without providing an

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argument for the screen width, the
default value of 80 will be used. So to

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test that, what I'm going to do is delete
the argument from the first five

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function calls, on lines 14 through 18.
I'll quickly do that now -

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just fast forward this bit.

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Okay, you can see that's done. Run the program now,

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and you can see we've now got a different
width for the first five lines.

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We haven't provided a screen argument, so we
get 80 characters - that's the default

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that we set, back up here on line one. So our banner

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looks horrible now, but I'm sure you
don't want to watch me deleting

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arguments. What I'll do is, just to
confirm that 80 is being used as the

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default, is change the next two lines to
80. Let's go ahead and do that.

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Alright, so I'm going to change line 19
to 80, and line 20 also to 80.

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Alright, so run the program now,

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and you can see the output of those two
lines I just changed, and I used the

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same width as the previous lines. Alright, so that's default parameter values.

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You provide the default value after the
parameter name, using the equal symbol,

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and you saw that on line one. That's the
same as when binding a variable to a

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value and it shouldn't look surprising.
Alright, so I'll leave you to tidy up the

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remaining four lines, and in the next video,
we'll talk about keyword arguments.

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See you in the next video.