Due Saturday, September 28, before midnight

Write a program donation.py that matches a blood donor’s blood type to the blood types of possible recipients:

For example (user input is shown in bold):

If the user inputs an invalid donor blood type, you should let them know:

For valid blood types, you may assume that the user enters upper-case letters. It’s fine to report an error for lowercase input:

A compression algorithm encodes data into a succinct format so that it’s cheaper to store or transmit. We’ll be using a variant of a real compression algorithm called run-length encoding (RLE).

For this problem, write a program called decoder.py that decodes a user-provided string to retrieve its human-readable form. For our version of RLE, if a string has a number, it indicates that you should copy the next letter that many additional times. For example (user input is shown in bold):

Note that any character following a number should print one more time than the number’s value (e.g., the 2y above prints y three times).

You may assume that any number in an encoded string will be just a single digit (i.e., in the range [0-9]). You may also assume that no number will appear at the end of an input string.

Hint: As you iterate through the characters in the encoded string, you can call the isdigit() function from the provided lab3 library on a character to determine whether it’s a number or a letter. The isdigit() function returns True if the character is a number and False otherwise:

To use the isdigit() function, don’t forget to import it from the lab3 library:

Most manufacturers offer bulk pricing discounts. Write a program pricing.py to compute a buyer’s total cost, including bulk discounts, when purchasing one or more products.

You should first ask the user how many products they plan to purchase. Then, for each product, ask for the product’s base price (prior to any discounts) and then ask how many of that product the user intends to buy. Apply the applicable bulk discount and print the discounted cost of that product. After the user has entered all the products, print the total price.

Apply discounts to products according to the following rules:

When computing a bulk discount, multiply the price by 1 - discount percentage. For example, if the user is buying 70 copies of an item that costs $100, you can apply the bulk discount of 7% and compute the total using:

You may assume that the strings the user inputs can be converted to the appropriate variable type to answer the question. That is, for questions asking "how many products", you’ll be given a string that can be converted to an int, and for questions asking about prices, you’ll be given a string that can be converted to a float.

Here are two example runs (user input is shown in bold):

Hint: This program will be larger than the other two. We strongly suggest that you test your program in small pieces as you write it rather than waiting until the end to test everything. You might want to start by asking "How many products would you like to buy?" and using the user’s response to execute a simple loop that prints that number of times. After confirming that part works via testing, you can proceed to ask the remaining questions.

Each lab will have a short questionnaire at the end. Please edit the Questions-03.txt file in your cs21/labs/03 directory and answer the questions in that file.

Once you’re done with that, run handin21 again.

Remember to run handin21 to turn in your lab files! You may run handin21 as many times as you want. Each time it will turn in any new work. We recommend running handin21 after you complete each program or after you complete significant work on any one program.