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Our users will need a way to interact with our program. In this video, we begin to offer that functionality by displaying a simple menu and waiting for input.
Code Samples
def run
loop do
puts "Address Book"
puts "e: Exit"
print 'Enter your choice: '
input = gets.chomp
case input
when 'e'
break
end
end
end
We call this by saying:
address_book.run
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[MUSIC]
0:00
Now that we have most of our classes set
up, we can work on input and output.
0:04
We're going to use a class from the Ruby
Standard Library to save things between
0:09
sessions.
0:13
This is a lot easier than you think.
0:15
Let's go ahead and
see how that works now, using WorkSpaces.
0:17
Okay, so we have our functionality
with our address book working so far.
0:21
We can add contacts.
0:26
We can add phone numbers and
addresses to our contacts.
0:27
And then, we can go ahead and
search through it if we want to.
0:31
So now, we're going to make this
more of a command line application.
0:35
So what that means is
we're going to have a menu
0:40
allowing our user to select something and
0:44
then work with it in the command line,
rather than from inside of a Ruby file.
0:49
Now the way that we're gonna do this
is create a method that loops through,
0:54
displays a menu and
then will call each of these methods,
0:59
depending on what the user enters.
1:03
So let's go ahead and create that.
1:07
Now, before we do that, let's go ahead and
look at all this stuff down here.
1:09
We're gonna just go ahead and
get it out of there.
1:12
So we have this address
book that we initialize.
1:16
And let's make a method called run
which will display our menu on a loop.
1:20
And that's all that we're gonna do to call
1:29
this run method which
will display our menu.
1:33
So now let's go ahead and write that.
1:38
Here is our run method.
1:40
Now we're gonna use a loop,
to display our menu.
1:47
And we are going to need
a way to exit the loop.
1:52
But, we'll write that in just a second.
1:57
So for
right now let's just display address book.
1:58
And let's go ahead and
give an option here.
2:03
If somebody enters
the letter E they can exit.
2:06
So we've got this little menu here.
2:11
This is just the start of it.
2:13
And then let's go ahead and
ask for their input.
2:15
We'll say, Enter your choice,
2:20
and then we will grab the input and
assign it to a variable.
2:26
We'll use the getString method, which
we'll just grab it from standard input.
2:30
And that will go in with a new line.
2:35
So we have to use the chomp
method to get just the character
2:38
that we're interested in.
2:41
And then let's go ahead and just make that
lower case so that when we search for
2:43
it we know what's going on.
2:47
Okay, now we know we're gonna
add on to this later, so
2:49
we're going to use a case
statement right now.
2:53
Since all we have is one option,
we're just gonna have one single option
2:55
in this case statement,
so when the user types
3:00
the letter E,
we're gonna break out of this loop.
3:08
Now let's go ahead and
ruin this and see what happens.
3:13
Address book, okay, let's type
the letter e and make sure it exits.
3:20
Uh-oh.
3:25
Undefined method input for address book.
3:26
I forgot an equals sign.
3:29
Okay, let's clear the screen and
run that again.
3:32
Okay.
Exiting works just fine.
3:36
Let me clear the screen.
3:38
We'll run this again.
3:40
If I type a,
okay we just get this menu again.
3:43
DE2, whatever.
3:46
Okay.
Good.
3:49
Now we know that E exits.
3:51
This is a good start for our menu so
we know that it's working.
3:53
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