Question & Answer: Extra Credit Programming Assignment Spamalot…..

Summer 2017 CS 1

Extra Credit Programming Assignment

Spamalot

Time due: 11:59 PM Thursday, August 10th

Introduction

Jee-mail, a small email service provider, has been receiving complaints from customers claiming that their inboxes are clogged with the dozens of spam email messages they receive each day. Consequently, Jee-mail has contracted with the Fruggle Corporation to design and build a spam detection system. Of course, since Fruggle gets all of its labor by exploiting El Camino students, you’ll be doing all of the programming.

Given one or more email messages, your program will have to classify each one as either spam or legitimate. Jee-mail wants you to build a point-based anti-spam system. Your program is to look for certain suspicious features in the email, such as frequent use of exclamation points (!), use of words like FREE, or excessive use of uppercase letters. Each time such a suspicious feature is found, you increase a score that indicates how suspicious an email is. If an email’s score exceeds 100 points, then it is classified as spam; otherwise, it is deemed legitimate. The detailed rules for scoring a message are in the Spam Rules section below.

Sample Transcript

Here is a sample transcript of the program, with boldface text representing the user’s input.

Enter the subject line of the email: MAKE MONEY FAST XTFWAQQQ

Enter the body of the email. Press Enter on an empty line to finish.

THIS IS YOUR CHANCE TO MAKE lots of moolah!

CLICK ON www.lotsofmoolah.com FOR MORE INFORMATION!

← the user just hit the enter key on this line

This email is classified as spam, because its spam score is 115.

Would you like to classify another email (y or n)? Quit

Please enter y or n.

Would you like to classify another email (y or n)? Y

Please enter y or n.

Would you like to classify another email (y or n)? y

Enter the subject line of the email: hi mom

Enter the body of the email. Press Enter on an empty line to finish.

Hi mom,

I hope you’re doing OK. My CS class is great, but the instructor is WEIRD!

I love you!

← the user just hit the enter key on this line

This email is classified as legitimate, because its spam score is 0.

Would you like to classify another email (y or n)? n

Number of spam messages: 1

Number of legitimate messages: 1

Input and Output Specification

The first line that your program must print out is exactly this (with one space after the colon):

Enter the subject line of the email:

Your program must then read the subject line the user types in. (It is not an error if the subject line is the empty string.) After that, your program must print out exactly this line:

Enter the body of the email. Press Enter on an empty line to finish.

Your program must then read the message body lines the user types in. The message body consists of zero or more lines. After your program reads an empty line, which indicates the end of the message, it must print out exactly one of these two messages, depending on whether applying the spam rules classified the message as spam or not:

This email is classified as spam, because its spam score is number.

This email is classified as legitimate, because its spam score is number.

In these messages, number is to be replaced by the appropriate spam score, such as 115, or 0, or 5.

After printing the classification message, your program must print exactly this (with one space after the question mark):

Would you like to classify another email (y or n)?

Your program must then read the line the user types in. If the user types only a lowercase y, the program must process another email, starting with the step where it prints the prompt for the subject line of the email.

If instead, the user types only a lowercase n, the program must print an empty line, then print the following two lines, then terminate:

Number of spam messages: number

Number of legitimate messages: number

In these messages, the first number is the number of messages that were classified as spam, and the second is the number that were classified as legitimate.

If the user types anything other than a single lowercase y or n in response to the question, the program must print out exactly the line:

Please enter y or n.

and repeat the prompt about classifying another email. It must repeatedly prompt the user until y or n is selected.

Spam Rules

The Jee-mail spam experts have come up with five rules, each of which can contribute some points to the spam score of a message. If the total spam score for the message is more than 100, the message is classified as spam; otherwise, it is considered a legitimate message. You must use only these five rules; do not improvise and make up your own. (Save that for when you start your own competing spam filter company.)

First, some definitions: a word in a string is a contiguous sequence of letters delimited either by non-letter characters or by the start or the end of the string. A letter may be upper- or lowercase. As an example, the string It’s like the old-fashioned 1980s! has these seven words: It s like the old fashioned s. A consonant is a letter other than one of these ten: aeiouAEIOU.

Here are the five rules. The first three relate to the subject line of the email, while the last two are concerned with the body of the message.

If the subject line has at least one word, and more than 90% of the words in the subject line consist of only uppercase letters, then add 30 points to the spam score. For example, a subject line of

GET A DIPLOMA FREE!!

meets this criterion.

If the last word of the subject line contains more than 3 consecutive consonants, then add 40 points to the spam score. Spammers often place random words at the end of a subject line to confuse some anti-spam software; this rules detects many of those random words. For example, this subject line earns the 40 point addition to the score:

This stock is going up, up, up! mqafrpxo!

If the subject line contains 3 or more contiguous exclamation points, then add 20 points to the spam score. This subject line qualifies for the 20 points, for example:

Make money fast!!! No experience necessary!!!!!

If the body of the message has at least one word, and more than 50% of the words making up the body of the email consist entirely of uppercase letters, then add 40 points to the score. For example, this email:

Subject: Greetings from your good friend

Body:

THIS IS YOUR CHANCE TO MAKE lots of moolah!

GO TO www.lotsofmoolah.com FOR MORE INFORMATION!

earns the 40 points because there are 17 words in the body of the email, 11 of which (64.7%) are entirely uppercase.

Each time one of the following special words is found in the body of the email, add 5 points to the spam score for that message. The letters in these words may be in either case (e.g., SeX is the same as sex):

buy

cheap

click

diploma

enlarge

free

lonely

money

now

offer

only

pills

sex

For example, this message would score 35 points, 5 for each of the words indicated in boldface:

Subject: Looking for cheap tickets?

Body:

You can find cheap! tickets ONLY on our website. Save money with this

great OfFeR!! Don’t be a cheapskate. Click now for this offer!

Notice that the “cheap” in the subject line is ignored by this rule, as is the word “cheapskate” in the second line of the body.

Functions You Must Write

We know that this will be the most complex program that many of you will have written in your programming careers to date, so we will make it easier for you by decomposing the problem for you.

To get full credit for this project, you must implement all of the following functions, using the exact function names, parameters types, and return types shown in this specification. The functions must not use any global variables whose values may change. (Global constants are all right.) In addition to testing your program as a whole, we will also test each of the following functions separately. That way, if your program doesn’t work overall but you correctly implemented some of the functions, you’ll still get some credit.

The functions you must implement are

getFirstWord

getLastWord

extractWord

isUppercase

makeUppercase

hasMultipleExclamations

isGibberishWord

Your solution should use these functions where appropriate (although you might not use every one of them). One reason is to help you get partial credit in the case where most of your program is correct, but a few of the function implementations are incorrect.

To help you implement these functions, you might choose to write additional functions as well. While we won’t test those additional functions separately, using them may help you structure your program more readably. If you find it helpful, you might have some of these seven required functions call other functions in that list.

When you turn in your solution, none of these seven required functions, nor any functions that they call, may read any input from cin or write any output to cout. (Of course, during development, you may have them write whatever you like to help you debug.) If you want to print things out for debugging purposes, write to cerr instead of cout. cerr is the standard error destination; items written to it by default go to the screen. When we test your program, we will cause everything written to cerr to be discarded instead — we will never see that output, so you may leave those debugging output statements in your program if you wish.

string getFirstWord(string text)

This function returns the first word in the string variable text. If text has no words, this function returns the empty string (i.e. “”). Here is an incomplete test driver for this function:

void test()

{

// This writes “Hello”

cerr << getFirstWord(“!!Hello, Fred”) << endl;

// This writes “greetings 9”

string msg = “greetings, mom, how are you?”;

string result = getFirstWord(msg);

cerr << result << ” ” << result.size() << endl;

// This writes “0”

string s = getFirstWord(” $@#%!!”);

cerr << s.size() << endl;

}

Hint: The string substr function may be of use in the implementation of this function.

string getLastWord(string text)

This function returns the last word in the string variable text. If text has no words, this function returns the empty string (i.e. “”). As an example, getLastWord(“MAKE MONEY FAST!!”) returns “FAST”.

Hint: The string substr function may be of use in the implementation of this function.

string extractWord(string& text)

This function returns the first word in the string that text is a reference to. If that string has no words, this function returns the empty string.

This function also modifies the string that text refers to. If that string has no words, then this function sets text to the empty string. Otherwise, it removes from text the first word of text and all non-letters preceding that first word. Here is an incomplete test driver:

void test()

{

string s = “***AMAZING!*** Do it, now!!”;

string w = extractWord(s);

// This writes “AMAZING” and “!*** Do it, now!!”