CMSC 104, Fall 2012

Homework 3

Basic Algorithms

Out: Fri 9/28/12
Due: Before 11:59 PM on Wednesday, October 3
Note that late homeworks will NOT be accepted.

The Objectives

To practice solving problems in a generic manner
To practice writing basic pseudocode for the solution of a problem

The Assignment

Two problems are given below. The answer to each problem will have two parts: the specific solution and the general solution.
You do not have to do any error checking of user input.
First solve each of the two problems shown below. You should show the specific answer to the problem using the numbers given. (25 points each, so make sure you show your work, no matter how simple you think it is)
Then write an algorithm for each of these two problems in pseudocode.(25 points each)

So, to recap: you must turn in 4 PARTS: a specific numeric solution to Problem 1, a general pseudocode solution to Problem 1, a specific solution to Problem 2, and a general pseudocode solution to Problem 2. Do not forget any of these parts!! Each is worth 25 points, for a total of 100 points.

Problem 1:

Ms. Match went to a store, spent half of her money and then $ 10 more. She went to a second store, spent half the money she had left and then $ 10 more. She then had no money left. How much money did Ms. Match have when she started out ?

Tips about the general pseudocode solution to problem # 1 :

You should solve this problem using the "working backwards" technique we applied in class to the "Kids in the Cookie Jar" problem. Hint: You probably want to consider using a while loop.
Ms. Match must always have no money left at the end.
The user should specify the number of stores.
The user should specify the "amount more" that Ms. Match spends at each store, but it will be the same amount at every store.

Problem 2:

Assume your grade in CMSC104 is based on the following (this is not the real formula for the class!):


 4 Homeworks (4% each) = 16%
 3 Projects  (8% each) = 24%
 3 Exams    (20% each) = 60%

 Total = 100%

If you have the following homework, project and exam grades at the end of the semester, calculate your final grade for the course:

  Homework 1 = 100/100  Project 1 =  85/100    Exam 1 = 95/100
  Homework 2 =  75/100  Project 2 =  75/100    Exam 2 = 85/100
  Homework 3 = 100/100  Project 3 =  70/100    Exam 3 = 70/100
  Homework 4 =  80/100

Tips about general pseudocode solution to problem # 2 :

You should allow the user to enter in each of the homework, project and exam grades separately
You do not have to use any loops--just have each item be requested in a separate DISPLAY/READ pair
You can assume the percentages will always be 4%, 8% and 20%. You should not ask the user to enter in these values.

Submitting the Assignment

Use "xemacs" to write your answers into a file called "hw3.txt", and then submit this file into the project "Hw3", by using the command:

linux1[6]% submit cs104_park Hw3 hw3.txt
linux1[7]%

CMSC104

Problem Solving & Computer Programming