17.1 CS 172 - Lab Stack Math In this lab, we will experiment with the Stack data structure and see how some problems lend themselves well to this data structure. The Stack As mentioned in class, Python 3 provides the LifoQueue class as part of the Queue library. To see how this is really just a wrapper around the basic list class below is our own Stack class that uses a list. This code has been provided to you below in a module called stackclass. py You MAY NOT change the structure of the provided Stack class in ANY way. Your post-fix logic should go in your main script. If you find yourself wanting to add more methods to the class, it means you are writing redundant code and should stop. The Stack class has the following public interface: __init__()

Write a grading program for a class with the following grading policies: a. there are two quizzes, each graded on the basis of 10 points. b. there is one midterm exam and one final exam, each graded on the basis of 100 points. c. the final exam counts for 50% of the grade, the midterm counts for 25%, and the two quizzes together count for a total of 25%. (do not forget to normalize the quiz scores. they should be converted to a percentage before they are averaged in.) any grade of 90 or more is an a, any grade of 80 or more (but less than 90) is a b, any grade of 70 or more (but less than 80) is a c, any grade of 60 or more (but less than 70) is a d, and any grade below 60 is an f. the program will read in the student’s scores and output the student’s record, which consists of two quiz and two exam scores as well as the student’s average numeric score for the entire course and final letter grade. define and use a structure for the student reco