The goal for this week is to do more structured programming in C, using functions and pointers to organize processing and update data. In particular, you will be working extensively with strings and arrays. Before beginning, make sure you are familiar with the following string functions: strlen, strcmp, strtok, strchr, strcat, atoi. Remember you can look them up in the unix "man" pages. You may want to use others as well.

• Readings: C text Chapters 4-6, Appendix B (string.h).
• Tutorials: Continue working with unix and emacs.
• Compilation: gcc -ansi -std=c99 -pedantic -Wall -Wextra -O pg#.c
• Submission: Upload your source file pg2.c to the webCT assignment page. Make sure that you hit SUBMIT after uploading. You can retrieve and resubmit as many times as you want before the deadline. If you retrieve, it's as if you never submitted, so make sure you have time to resubmit! If you need to explain anything in general, include a README plain text file with your submission. Anything not on webCT by the deadline gets a 0 = no credit. Also bring a printout of your source code to class on the due date.
• Collaboration: This is an individual assignment. Remember that you may use or adapt code from your texts and lectures, but you MUST include a comment to cite the original source.
• Help: check the TA info course webpage for hours when help will be available in the CS lab. Hopefully we won't have too many more snow days!
• Grading: 5 points style, efficiency & submission, 40 points functionality = 45 total. -5 points if there are any warnings using the required compilation options. 0 points if it doesn't compile (has errors, no a.out created). Any violation of the implementation details (below) will result in a 0 grade for the assignment.

The Problem: Phone Numbers

The purpose of this program is to process phone numbers by giving feedback on the type of phone number entered, and also by suggesting various character pneumonics by which to remember them.

There will be four types of phone numbers: toll-free, local land, local cell and long distance. Toll free numbers have one of these four area codes: 800, 888, 877, 866. Local phone numbers will be identified according to your home state. Use constants to store the most common land and cell (one of each) area codes in your hometown. (The examples below are for someone living in Baltimore.) All other area codes will be identified as long distance numbers.

The fun part of the program is getting suggestions on character pneumonics to use to remember the phone numbers. Look at a phone to see what characters are associated with each number button. '1' and '0' do not have any characters. Most buttons have 3 and two have 4 characters on them. Display a table which shows the 7 digit part of the entered phone number (no area code) and below each digit a column of letters that could be chosen for that digit.

In order to eliminate some pneumonic choices, remove any characters that do not appear in the name associated with the number. Redisplay the number and character options in table format. Lastly, display all the possible combinations for the number. If any digits do not have character options, then continue to use the digits themselves.

The operation of the program is as follows:

• Get a 10 digit phone number and corresponding name. The phone number could be in one of two forms: ###-###-#### or (###)###-####. The name can be any number of words. All this data must be entered on one line of input!
• Check the phone number for validity: it must have one of the above formats with digits 0-9 where the # signs appear. If it is not valid, then output an error message and quit the program.
• Process a valid number by stating whose phone number it is and what type of line it is. For the local lines, you must use "probably" in your output because land and cell area codes are not strictly distinguished.
• Further process each valid number by performing the pneumonic operations detailed above.

Implementation Details:

• Your program must adhere strictly to the sample runs below.
• Your program only needs to process one phone number each time it is run.
• You must not use any global variables.
• You must use arrays to simplify the processing.
• Make your code as efficient as possible, both in terms of space and time!! This means avoiding unnecessary copying of data.
• Hint: just because the table is displayed with the characters in columns doesn't mean you have to store the data that way...

Grading: here is a quick breakdown of the functionality to motivate you to solve this problem incrementally!

• [2] Store your hometown area codes as constants.
• [3] Get and parse the input line into number and name.
• [5] Do error checking on the phone number.
• [7] Display the name and phone number type.
• [7] Display the table of all possible character choices.
• [8] Display table without non-related characters.
• [8] Display all possible character combinations.

Here are some examples of invalid phone numbers:

866-394=4930
443-4567-543 
443-2a4-54i3 
410-516-411723
(234) 432-2345 

Here are two sample runs:

------------------------
enter 10-digit phone number xxx-xx-xxxx or (xxx)xxx-xxxx and name:
410-231-4059  Mr.  &  Mrs. Smith
Mr.  &  Mrs. Smith's number is probably a local land line

Associated characters:
2314059
ad g jw
be h kx
cf i ly
      z

After eliminating non-related characters...
2314059
   h   
   i 

Possible pneumonics:
231h059
231i059

-------------------------
enter 10-digit phone number xxx-xx-xxxx or (xxx)xxx-xxxx and name:
(800)347-7866 Firestone
Firestone's number is a toll-free line

Associated characters:
3477866
dgpptmm
ehqqunn
firrvoo
  ss   

After eliminating non-related characters...
3477866
eirrtnn
f ss oo

Possible pneumonics:
eirrtnn
eirrtno
eirrton
eirrtoo
eirstnn
eirstno
eirston
eirstoo
eisrtnn
eisrtno
eisrton
eisrtoo
eisstnn
eisstno
eisston
eisstoo
firrtnn
firrtno
firrton
firrtoo
firstnn
firstno
firston
firstoo
fisrtnn
fisrtno
fisrton
fisrtoo
fisstnn
fisstno
fisston
fisstoo