ECE-203 Homework Week 4

ECE-203 Programming for Engineers
Homework Week 4
For faster sorting of letters, the United States Postal Service encourages companies that send large
volumes of mail to use a bar code denoting the zip code.
*********************** ECRLOT ** CO57
CODE C671RTS2
JOHN DOE CO57
1009 FRANKLIN BLVD
SUNNYVALE CA 95014-5143
Frame bars
{
{
{
{
{
{
Digit 1 Digit 2 Digit 3 Digit 4 Digit 5 Check
Digit
The encoding scheme for a five-digit zip code is shown in the above figure. The five zipcode digits
are encoded using five clusters of bars, where each bar is one of two heights: short or tall. The five
encoded digits are followed by a check digit, which is computed as follows:
• Add up all the digits in the zipcode to make the sum Z
• Choose the check digit C so that Z + C is a multiple of 10
For example, the zipcode 95014 has a sum of Z = 9 + 5 + 0 + 1 + 4 = 19, so the check digit C is 1
to make the total sum Z + C equal to 20, which is a multiple of 10.
Each digit of the zipcode, as well as the check digit, is individually encoded according to the table
below, where 0 denotes a short bar and 1 a tall bar:
Digit Bar 1 Bar 2 Bar 3 Bar 4 Bar 5
(weight 7) (weight 4) (weight 2) (weight 1) (weight 0)
1 0 0 0 1 1
2 0 0 1 0 1
3 0 0 1 1 0
4 0 1 0 0 1
5 0 1 0 1 0
6 0 1 1 0 0
7 1 0 0 0 1
8 1 0 0 1 0
9 1 0 1 0 0
0 1 1 0 0 0
Decoding from the bar pattern to the original digit can be easily computed using the column weights
7, 4, 2, 1, and 0. For example, 01100 (short, tall, tall, short, short) decodes to:
0 × 7 + 1 × 4 + 1 × 2 + 0 × 1 + 0 × 0 = 6
Unfortunately, the digit 0 is an exception. If you apply the same decoding algorithm for 0, you end
up with:
1 × 7 + 1 × 4 + 0 × 2 + 0 × 1 + 0 × 0 = 11
1
So, bar clusters that decode to 11 will require special handling since the true decoded value is
actually 0.
Write a program that asks the user for a zip code and prints the bar code. Use ! for tall bars and
. for short bars. For example, if the user entered 95014, your program should produce:
!!.!.. .!.!. !!... ...!! .!..! ...!!!
Notice how there is an extra tall bar at the start and another at the end. These are called the frame
bars and they are used to determine where the code starts and stops.
You will need to implement the following two functions:
printDigit(digit)
printBarCode(zip code)
which you will use to implement the encoding algorithm. printDigit() should accept a single
parameter (representing a digit between 0 and 9) and produce a single ”cluster” of bars. The
printBarCode() function should accept a single parameter representing a full 5 digit zipcode and
produce a full bar code of 5+1 clusters with frame bars. Each cluster should be crafted using
printDigit().
Name your program barcode.py and save its output as barcode.txt. Your output file should show
your program testing the following zipcodes: 19104, 33139, 02201, 49726, 70802, 38103, 98104, and
49918.
Submitting Your Assignment
Create a zip file with the following structure:
.HW4 abc123.zip
.barcode.py
.barcode.txt
name your zip file using your Drexel user id. For example: HW3 abc123.zip. Upload your zip file
to learn.drexel.edu using the assignment submission link found on the course website.
Points will be deducted for improperly packaged submissions.
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