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Hello, welcome to the third challenge
for the section 20, part of the course.

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I’m in the section 20 workspace,
and I've got two projects,

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the challenge_3 project and the
challenge_3_solution project.

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So, as usual the solution is my
solution, and the challenge_3

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project is the shell that I'm giving
you, that has the beginnings of

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the project that you can work on.

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So, let's talk about this project.

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This is a fun challenge.

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This challenge has two parts,
and it's all about understanding

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stood set and stood map.

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We're going to use the
sets and the maps together.

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We're going to be reading words
from a text file provided,

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I'm providing that for you.

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The text file is called words.txt and
I'll show that to you in just a moment.

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And it contains the first
few paragraphs from the book,

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The Wonderful Wizard of Oz.

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So, the idea here is, the first part
of the challenge is you're going to

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read each word from that file and count
how many times it occurs in the file.

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And then display that information.

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So, what we get is a
listing similar to this.

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This is just the first few words.

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You can see that the word Aunt
appears five times in the text,

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Dorothy eight, Dorothy's once,
Em 5, Even once, and from once.

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Now you'll also notice that
these words are displayed just

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like this A, D, E, F, they're
displayed in ascending order.

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And then right next to the
word, we have the number

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of times that it occurs.

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Simple!

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So, please use a map for this, and
make sure that your key value pair

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is a string.int, that makes sense.

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This is your key right here.

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The word and the value is the count.

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And the functions that I've
written for you assume this, so

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make sure you use the string.Int.

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So, that's part one.

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And let me show you the file real
quick before we talk about part two.

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Here's the file, you can see
it right here in words.txt.

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There's the file and it's the first, I
think five, or six, or seven paragraphs

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from The Wonderful Wizard of Oz.

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So, you can see Dorothy appears
here, and it's really easy to

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check your work in code light.

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For example, if I just double click
Dorothy, you can see the Dorothy

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appears once, twice, three times, four,
five, six, seven, eight, nine times.

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So, it's really easy to tell just
because it highlights it in yellow, and

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it also gives you the line number that
it appears on, which is really cool.

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Because that's what part two
of the challenge is all about.

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Alright, so let me get
back to the description.

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So, that's part one, and then
in part two what I want is, same

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idea, I want to read all the words
from the file and I don't really care how many

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times they occur. I've already got that up here.

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What I want to know is what
line numbers do they occur on.

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I want to see all the line numbers.

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So, in this case, we can do
this one, Aunt appears on line

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number 2, 7, 25, 29 and 48.

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Now, it might appear more than
once on each line, I don't want

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you to say 2-2, 7-7-7 and so forth.

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Just the line number
should appear only once.

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So, again the word should be ascending
in order and the line number should

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be ascending in order in here as well.

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So, one more time, Aunt appears
on line 2, 7, 25, 29 and 48.

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So, we can come over here to words.txt,
we can find Aunt which is right there.

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So, there it is 2, 7, 25, 29 and 48.

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It's a nice easy way
to test your output.

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That's the challenge.

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So, let me go back to the
description and we'll talk a

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little bit more about this.

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For this part, for part two,
please use a map of string, set,

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Int, key value pairs, right.

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So, the key is the word, the string,
and the value is a set of integers.

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We did this in the
description for the map video.

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This is just going to apply it now.

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For this one as well, for part
two, consider using a string

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stream to process your words.

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So, in other words, read the
line from the file into a string.

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And then use a string stream to process
that string, so you can extract the

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words from it really, really, easily.

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I've also provided the basic
shell for both of these.

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And I'll show you that in a second.

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And I've provided a function
called clean string.

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And you can pass a word into
that function, and it's going to

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return the clean version of it.

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So, it's going to remove any
trailing periods, or semicolons,

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or colons, and things like that.

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And you could tweak that
function however you like.

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I'll show you the code in a second.

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That's it. Let me run this program,
so you can see the output.

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And you can see all the display
I'm going to scroll all the way up

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to the top, it's running part one
and then it's running part two.

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Here's part one, Aunt appears five
times, Dorothy appears eight times,

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Em appears five times, and you go all
the way through Aunt and lowercase

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Aunt would be different words.

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You can choose to make them all
upper, or lower, or do whatever you

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like with that just to have fun.

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So, in this case, let's look
at some of the common words in

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English, the ‘a’ appears 20 times,
‘and’ appears 32 times, ‘the’ is

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a very popular word, and there
is ‘the’, it appears 43 times.

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So, that's part one.

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Again notice that this is
sorted in ascending order.

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Now here's part two, we have
the word and the occurrences

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of that word with line numbers.

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So, Aunt appears on lines 2, 7,
25, 29 and 48, here you can see

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that Henry appears on lines 2,
6, 35, 45, and 50, ‘There’ with

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the capital T appears on line 2.

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And you can see the rest.

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They're all here.

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So, that's the challenge.

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It's not that hard.

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Don't overthink this challenge.

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Let the STL do the work for you.

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Don't start messing around, and trying
to get into the details of this,

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just let the STL do the work for you.

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Think abstractly.

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So, that's a sample run, and let me
show you the code that I'm giving you.

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It's right in here in
challenge_3 project, main, CPP.

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So, I'll double click there, and let
me scroll down to the main real quick.

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There's your main, right here.

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It's running part one
and then part two.

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And for each part, I'm, here's part
two for example, there's the file.

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I'm opening the file. I'm closing the file.

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So, think of part one and part
two as unique little functions

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that each one opens the file,
each one closes the file.

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So, you can see in part one right
here, my map is called words.

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And it's a map of string,
Int, key value pairs.

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I've got some variables here.

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I've got my file which I'm opening.

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I'm checking to see if
it was open successfully.

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And if it is then you write
this code, and then when you're

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done with your code, you call
that function right there.

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Display words, pass it in the
map and I've written the code

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that's going to display that
all in a nice little format.

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But this is the code you need to
implement here for part two, same idea.

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Here's my map words.

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This time, it's a map of key
value pairs where the key is a string

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and the value is a set
of integers as we discussed.

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I'm opening the file.

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I'm closing the file here
if it was open successfully.

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You implement this code, when you're
done processing the map, pass the

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map into display words, and it'll
display all that information for you.

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Now those two functions I
wrote up here, this is display

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words for part one, and this
is display words for part two.

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The only difference is this one
expects string, Int, key value pairs.

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This one expects
obviously a map of those.

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This expects a map of string and
a set of Int key value pairs.

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You can totally erase
these, and do them yourself.

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I would actually encourage
you to do that but they're

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there for your benefit.

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Get rid of them, and do them when
you're on your own if you like.

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And then here's the
clean-string function.

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It expects a string, and you can
see the code is dead simple for each

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character in the string if it's a
period, or a comma, or a semicolon, or

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a colon, I'm just not processing it.

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Otherwise, I'm just appending the
character to the new string and

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returning it, so that's it I'm
just filtering on those characters.

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You can add some, remove
some, or do whatever you like.

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That's it.

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That's the challenge.

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Again, have fun.

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This is actually a fun challenge,
and it's really easy to do.

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But you'll be surprised
how easy this is to do.

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It doesn't seem so easy, but it really
is, and as I said the best advice I

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can give you is don't overthink this.

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Let the STL do its job
that's what it's good at.

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Okay, so I will see you in the
next video in the solution.

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So, have fun!