Introduction to Computer Science II

Homework 4

Due by 11:50am on Tuesday, February 1

Reading

Read chapters 8 and 9 and the week 4 lecture notes.

Problems

Solve the following by implementing the corresponding functions in homework4.py, increment.py, and bmi.py. When done, submit all three files through D2L.

1. Write a container class called PriorityQueue. The class should support methods:

insert(n): Takes a number n as input and adds it to the container
min(): Returns the smallest number in the container
removeMin() Removes the smallest number in the container
isEmpty(): Returns True if container is empty, False otherwise

In addition to these methods your class shoudl support the len() function as shown below.

Usage:
>>> pq = PriorityQueue() >>> pq.insert(3) >>> pq.insert(1)>>> pq.insert(5) >>> pq.insert(2) >>> pq.min() 1 >>> pq.removeMin() >>> pq.min() 2 >>> len(pq) 3 >>> pq.isEmpty() False

2.    Do problem 8.16 in the textbook.

3.    Do problem 8.18 in the textbook.

4.    Do problem 8.39 in the textbook.

Usage:
>>> dude = Hacker()
>>> snoopy = Dog()
>>> garfield = Cat()
>>> tweety = Animal()
>>> tweety.speak()

>>> garfield.speak()
Meeow!
>>> snoopy.speak()
Wooof!
>>> dude.speak()
Hello World!
>>> kingkong = Primate()
>>> kingkong.speak()
Boooh

5. [Lab] Implement in increment.py a GUI that has two buttons:

The button labeled Increment will increment an integer n, initially 0, and the button labeled Show will show the value of n in a popup window. Hint: Make n a global variable.

Usage:
After starting the GUI, if you were to click the Show button, a popup window will appear showing the initial value of n:

Click OK. Now suppose you click the Increment button once and then ckick Show. You will see another popup window:

Click OK. Now suppose you click the Increment button three times and then ckick Show. You will see another popup window:

6. [Lab] Implement in bmi.py an app that allows users to compute their body mass index (BMI), which is defined in Practice Problem 5.1 of your textbook. Your GUI should look as follows:

After entering the weight and height and then clicking the button, your BMI should appear in the Entry labeled BMI:

Make sure that your GUI is user friendly by deleting the entered weight and height so that the user can enter new inputs without having to erase the old ones.