Homework Assignment H04: Processing a file

Purpose

We are going to continue our problem-solving education by writing a program that processes a file and calculates statistics. Operating with data files is a very powerful and useful tool. TextIO makes reading in from files very easy. I recommend you use TextIO instead of java.util.Scanner.

We will also get more practice using Eclipse to make our programming life easier.

Tasks

1. Create a package named edu.ics111.h04 in your ICS111-workspace project

This is where we will put all our classes for homework 04.

2. Using the Programming Algorithm write a program that processes a data file of visitor information

Write a program that will compute and print the total visitors from all the countries together and their average spending.

The data file contains visitor information about visitors to Hawaii from various countries. Each line of the file contains a country name, followed by a colon ‘:’ followed by the number of visitors for that country, followed by a colon ‘:’, followed by the dollars spent by the visitors. The number of visitors is a number of type int. The dollars spent is a number of type double. However, for some countries, no data was available. In these lines, the data is replaced by a comment explaining why the data is missing. For example, several lines from the file might look like:

Canada: 135132: 140020521.00
Bulgaria: no report received
Mexico: 200123: 98298734.12

The program should also report the number of countries for which data was not available. The name of the file is “visitors.dat”.

You can download an example visitors.dat file to test your code. You should create your own files for testing.

Read and understand the problem.

Do you understand what the program needs to do?

Create the Java file for your program and insert the Java boilerplate

Use the steps from H02 to create your Java program and boilerplate code.

Write the steps to solve the problem as comments in main and refine them

“What are the steps needed to solve this problem?” Write them down as comments in the main method. Once you have the steps start refining them till you can write Java code.

How are you going to process the file?
How will you know the file is processed?
- To complete this program, you’ll need one fact about file input with TextIO that was not covered in Subsection 2.4.4. Since you don’t know in advance how many lines there are in the file, you need a way to tell when you have gotten to the end of the file. When TextIO is reading from a file, the function TextIO.eof() can be used to test for end of file. This boolean-valued function returns true if the file has been entirely read and returns false if there is more data to read in the file. This means that you can read the lines of the file in a loop while (TextIO.eof() == false)…. The loop will end when all the lines of the file have been read.
How are you going to process each line?
- You can read in the whole line as one String then process the String using String functions like indexOf or lastIndexOf and substring.
- Or you can use TextIO to read in parts, read and ignore characters up to the first colon. Then read the characters up to the second colon into a variable of type String. Try to convert the string into a number, and use try..catch to test whether the conversion succeeds. Do the same for the characters after the second colon.
- Or you can use your own steps.

Grading Rubric

Criterion	Excellent (100%)	Satisfactory (75%)	Borderline (50%)	Unsatisfactory (25%)	Poor (0)
Adherence to standards - 2 points Does it conform to standards in every detail?	No errors.	Minor details of the assignment are violated, or poor choices are made where the assignment is unclear.	Significant details of the assignment or the underlying program intent are violated, but the program still fulfills essential functions.	Significant details of the assignment or the underlying program intent are violated, but the program still fulfills some essential functions.	Misses the point of the assignment.
Breakdown (modular design) - 1 point Does it demonstrate good modular design?	No errors.	1-3 minor errors.	> 3 minor errors OR 1 major error.	2 major errors	> 2 major error.
Correctness of code - 5 points Does it work? Does it pass JUnit?	Passes all tests.	Works for typical input, may fail for minor special cases.	Fails for typical input, for a minor reason.	Fails for typical input, for a major reason.	No.
Documentation, and style - 2 points Is it clear and maintainable? Does it pass CheckStyle?	No errors.	1-3 minor errors.	> 3 minor errors OR 1 major error.	2 major errors	> 2 major error.

Turning in the Assignment

The assignment is due on Friday, September 24th at 11:55pm. You may turn it in early.

Conduct a personal review of your code before turning it in. Does your code follow the Java Coding Standard?
- Is it clear and well commented?
- Does it pass Checkstyle?
Test your code.
- Does it produce the correct output? Calculate the values by hand then check to see if it gets the math right.
Export your ICS111-workspace project by choosing File -> Export. Name the zip file H04.zip.
Sign into Laulima, then navigate to the ICS111 site. In the left hand side of the site, there is an Assignments tab/link. Click on it and view all of the posted assignments. Select the assignment that you want to turn in and attach your H04.zip file and accept the honor pledge to submit the assignment.