For faster sorting of letters, the postal service encourages companies that send large volumes of mail to use bar code denoting the ZIP code (see figure below).
Student XXXX
PO Box 34689 Jeddah
21478
KSA
There are full height frame bars on each side. The five encoded digits are followed by a check digit, which is computed as follows. Add up all digits, and choose the check digit to make the sum a multiple of 10. For example, the sum of the digits in the ZIP code 21478 is 22, so the check digit is 8 to make the sum equal to 30.
Each digit of the ZIP code, and the check digit, is encoded according to the following table, where 0 denotes a half bar and 1 a full bar.
Note that they represent all combinations of two full and three half bars. The digit can be computed easily from the bar code using the column weights 7, 4, 2, 1, 0. For example, 01100 is
0.7+1.4+1.2+0.1+0.0 = 6
The only exception is 0, which will yield 11 according to the weight formula.
Write a program that asks the user for a ZIP code and prints the bar code. Use ‘:’ for half bars, | for full bars. For example, 21478 becomes
| | : : | : : : : | | : | : : | | : : : | : : | : | : : | : |
You are requested to design the appropriate classes and supply the appropriate methods. Your solution must be Object Oriented (OO).
You will certainly need a class and associated methods for decoding and printing the bar-codes.
Whether you would make a class to encapsulate the input and output is up to you, or your instructor.
The instructions for printing the bar-code looks complex, but it is the easy part, and fun to do.
Do some high-level planning (classes, methods, state variables, etc.) before plunging into the pseudocode, or actual coding.
Post if you have progress or problems.
To design the appropriate classes and methods for the given problem, we need to identify the entities and their relationships.
One possible way to structure the code can be to have a class called "ZipCode" that represents a ZIP code. This class should have attributes to store the ZIP code value and the check digit. It should also have methods to compute the check digit and generate the barcode representation.
Here is an example implementation in Python:
```python
class ZipCode:
def __init__(self, zipcode):
self.zipcode = zipcode
self.check_digit = self.compute_check_digit()
def compute_check_digit(self):
# Add up all digits to compute the check digit
digits_sum = sum(map(int, list(self.zipcode)))
return (10 - (digits_sum % 10)) % 10
def generate_barcode(self):
barcode = []
for digit in self.zipcode:
barcode.append(self.encode_digit(int(digit)))
barcode.append(self.encode_digit(self.check_digit))
return " | ".join(barcode)
@staticmethod
def encode_digit(digit):
# Encode the given digit using the barcode table
weights = [7, 4, 2, 1, 0]
if digit == 0:
return "| |"
barcode = []
for weight in weights:
if digit >= weight:
barcode.append("|")
digit -= weight
else:
barcode.append(":")
return " ".join(barcode)
# Example usage
zipcode = input("Enter the ZIP code: ")
zip_obj = ZipCode(zipcode)
barcode = zip_obj.generate_barcode()
print(barcode)
```
In this implementation, the `ZipCode` class represents a ZIP code. It has an `__init__` method that initializes the `zipcode` attribute with the provided ZIP code and computes the check digit using the `compute_check_digit` method.
The `generate_barcode` method generates the barcode representation for the ZIP code. It uses the `encode_digit` method to encode each digit and appends the encoded digit to the barcode list. The method then joins the barcode list with `" | "` as the separator and returns the resulting string.
The `encode_digit` method takes a digit as input and encodes it using the barcode table. It uses the `weights` list to calculate the encoded digit based on the column weights. If the digit is 0, it returns `| |` as the encoding, representing a half bar.
Finally, an example usage is shown where the user is prompted to enter a ZIP code. The entered ZIP code is used to create a `ZipCode` object, and the barcode is generated using the `generate_barcode` method. The barcode is then printed to the console.